Fall cooking has always brought out my favorite ingredients. I get excited about squash season the way some people get excited about pumpkin spice everything. But let’s be honest – I don’t always want to spend hours in the kitchen making something fancy when the weather gets cooler.
That’s why gratins are my go-to side dish during fall and winter. I can slice everything up, layer it in a dish, and let the oven do most of the work while I’m getting other things done around the house. The prep happens when I’m already chopping vegetables for dinner anyway. No extra mess to deal with.
Love butternut squash but tired of the same old roasted version? This gratin is for you. Want something that feels special but doesn’t stress you out? Same. The sage makes it smell amazing, and honestly, it’s fancy enough for company but easy enough for a regular Tuesday night.
Why You’ll Love This Butternut Squash Gratin
- Perfect fall comfort food – The creamy, cheesy layers of tender butternut squash with aromatic sage make this the ideal side dish for cozy autumn dinners and holiday gatherings.
- Impressive presentation – This gratin looks fancy enough for company but is surprisingly easy to make, giving you that restaurant-quality dish at home.
- Make-ahead friendly – You can assemble this gratin earlier in the day and pop it in the oven when you’re ready, making dinner prep so much easier.
- Rich and creamy texture – The combination of heavy cream, parmesan, and perfectly cooked squash creates layers of pure comfort in every bite.
- Simple ingredients – Most of these pantry staples and basic ingredients are things you likely already have on hand, making this an accessible recipe to try.
What Kind of Butternut Squash Should I Use?
Any butternut squash you find at the grocery store will work great for this gratin, but there are a few things to keep in mind when selecting one. Look for a squash that feels heavy for its size and has a firm, matte skin without any soft spots or blemishes. The tan-colored neck should be long and thick since that’s the part you’ll be slicing for the gratin – the bulbous bottom contains the seeds and less usable flesh. If you’re short on time, many stores sell pre-cut butternut squash, though it will cost more and you’ll want to use it within a day or two for the best flavor.
Options for Substitutions
This gratin is pretty forgiving when it comes to swaps, so here are some easy substitutions you can make:
- Butternut squash: You can swap butternut squash with delicata squash, acorn squash, or even sweet potatoes. Just keep the same thickness when slicing – about 1/8 inch works best for even cooking.
- Heavy whipping cream: If you want something lighter, try half-and-half or whole milk, though the sauce won’t be quite as rich. For dairy-free, use full-fat coconut milk or cashew cream.
- Shallot: No shallots? Use about 1/3 cup of finely diced yellow onion instead. It’ll give you that same mild, sweet flavor.
- Fresh sage: Fresh sage really makes this dish shine, but if you only have dried, use about 1 teaspoon instead of the 15 fresh leaves. Add it to the cream sauce rather than using it as garnish.
- Parmesan cheese: Gruyere, aged cheddar, or pecorino romano all work well here. Just stick with hard, aged cheeses that melt nicely and have good flavor.
- Vegetable stock: Chicken stock works just fine if that’s what you have on hand. You could even use water in a pinch, though you’ll lose some depth of flavor.
Watch Out for These Mistakes While Baking
The biggest mistake when making butternut squash gratin is cutting your squash slices too thick, which leads to uneven cooking and a casserole that’s raw in some spots and overcooked in others – stick to that 1/8 inch thickness for the best results.
Another common error is not cooking your sage-infused cream sauce long enough, so make sure it thickens properly before pouring it over the squash, and don’t skip browning the butter first as this adds a nutty flavor that pairs perfectly with the sage.
To prevent a watery gratin, pat your sliced butternut squash dry with paper towels before layering, and cover the dish with foil for the first 30-40 minutes of baking to ensure the squash cooks through before the top gets too brown.
Finally, let the gratin rest for at least 10 minutes after baking so the sauce can set up properly and make serving much cleaner.
What to Serve With Butternut Squash Gratin?
This rich and creamy gratin makes a perfect side dish for roasted chicken, pork tenderloin, or even a simple grilled steak since the sweet squash pairs beautifully with savory proteins. I love serving it alongside a crisp arugula salad with lemon vinaigrette to cut through all that creamy goodness, or with some roasted Brussels sprouts for a complete fall-inspired meal. If you want to make it the star of the show, just add some crusty bread and a light green salad for a satisfying vegetarian dinner. The sage and parmesan flavors also work really well with roasted turkey, making this gratin a great addition to your holiday table.
Storage Instructions
Refrigerate: This gratin keeps really well in the fridge for up to 4 days. Just cover it tightly with foil or plastic wrap once it’s cooled completely. The flavors actually get even better after a day or two, so don’t worry about making it ahead for dinner parties!
Freeze: You can freeze this gratin for up to 3 months, either before or after baking. If freezing unbaked, wrap it tightly in plastic wrap and foil. If freezing after baking, let it cool completely first, then wrap well and freeze in individual portions if you want.
Reheat: To warm up leftovers, cover with foil and bake at 350°F for about 15-20 minutes until heated through. If it’s frozen, thaw it overnight in the fridge first. You might want to add a splash of cream or stock if it looks a bit dry after reheating.
| Preparation Time | 20-30 minutes |
| Cooking Time | 30 minutes |
| Total Time | 50-60 minutes |
| Level of Difficulty | Medium |
Estimated Nutrition
Estimated nutrition for the whole recipe (without optional ingredients):
- Calories: 1600-1750
- Protein: 40-46 g
- Fat: 120-130 g
- Carbohydrates: 100-115 g
Ingredients
For the cream sauce:
- 3 tbsp butter
- 1 large shallot, finely minced
- 4 garlic cloves, coarsely chopped
- 1 tbsp all-purpose flour
- 1 cup vegetable broth, low-sodium
- 1 cup heavy cream
- 15 whole sage leaves
- 1/2 tsp black pepper
- 1/2 tsp onion powder (optional)
For assembly:
- 2 lb butternut squash, peeled and cut into 1/8 inch half-rounds
- 3 oz parmesan cheese, grated
- 1 tsp fresh chives, chopped (optional)
- Butter for greasing baking dish
Step 1: Prepare the Butternut Squash
- 2 lb butternut squash, peeled and cut into 1/8 inch half-rounds
Peel the butternut squash thoroughly and slice it into 1/8-inch thick half-rounds.
Remove and discard the seeds.
Set the prepared squash aside for layering later.
If you have extra squash from the bottom, you can save it for another use.
Step 2: Make the Creamy Sage Sauce
- 3 tbsp butter
- 1 large shallot, finely minced
- 4 garlic cloves, coarsely chopped
- 1 tbsp all-purpose flour
- 1 cup vegetable broth, low-sodium
- 1 cup heavy cream
- 1/2 tsp black pepper
- 1/2 tsp onion powder (optional)
- 15 whole sage leaves
In a small saucepan, melt the butter over medium heat.
Add the finely minced shallot and coarsely chopped garlic, cooking until fragrant for about 1 to 2 minutes.
Sprinkle in the all-purpose flour and whisk continuously with a wooden spoon to form a roux, letting the mixture thicken.
Gradually pour in the low-sodium vegetable broth, whisking constantly to prevent lumps.
Add in the heavy cream, black pepper, onion powder (if using), and whole sage leaves.
Stir and heat gently until smooth; do not let it come to a boil.
Step 3: Prepare Baking Dish and Layer Ingredients
- butter for greasing baking dish
- cream sauce from Step 2
- butternut squash from Step 1
- parmesan cheese (portion from 3 oz, reserved remainder for topping)
Preheat your oven to 400ºF (200ºC).
Use a small knob of butter to grease a 9 x 13-inch baking dish well.
Pour one-third of the prepared cream sauce from Step 2 into the bottom of the greased baking dish.
Sprinkle a small amount of the grated parmesan cheese over the sauce.
Arrange the butternut squash slices (from Step 1) in two or three overlapping rows on top of the sauce and cheese.
I like to overlap the squash for an attractive, rustic look.
Drizzle the remaining two-thirds of the cream sauce evenly over the squash layers.
Step 4: Bake the Gratin
- remaining parmesan cheese from 3 oz
Cover the baking dish with a sheet of parchment paper placed directly onto the gratin’s surface, then wrap with aluminum foil on top to prevent the foil from touching the food.
Place the covered baking dish in the preheated oven and bake for 20 minutes.
After this initial bake, remove both the foil and parchment paper, then sprinkle the remaining parmesan cheese evenly over the gratin.
Return the dish to the oven and bake uncovered for another 10 minutes, or until the top is golden and crispy.
Step 5: Garnish and Serve
Take the finished gratin out of the oven and let it cool slightly for a couple of minutes.
Sprinkle with the chopped fresh chives for a pop of color and mild onion flavor, if desired.
Serve the gratin immediately while it’s warm and bubbly.
For a bit of extra richness, I sometimes drizzle a small amount of browned butter over the top before serving.
Easy Sage Butternut Squash Gratin
Ingredients
For the cream sauce:
- 3 tbsp butter
- 1 large shallot, finely minced
- 4 garlic cloves, coarsely chopped
- 1 tbsp all-purpose flour
- 1 cup vegetable broth, low-sodium
- 1 cup heavy cream
- 15 whole sage leaves
- 1/2 tsp black pepper
- 1/2 tsp onion powder (optional)
For assembly:
- 2 lb butternut squash, peeled and cut into 1/8 inch half-rounds
- 3 oz parmesan cheese, grated
- 1 tsp fresh chives, chopped (optional)
- butter for greasing baking dish
Instructions
- Peel the butternut squash thoroughly and slice it into 1/8-inch thick half-rounds. Remove and discard the seeds. Set the prepared squash aside for layering later. If you have extra squash from the bottom, you can save it for another use.
- In a small saucepan, melt the butter over medium heat. Add the finely minced shallot and coarsely chopped garlic, cooking until fragrant for about 1 to 2 minutes. Sprinkle in the all-purpose flour and whisk continuously with a wooden spoon to form a roux, letting the mixture thicken. Gradually pour in the low-sodium vegetable broth, whisking constantly to prevent lumps. Add in the heavy cream, black pepper, onion powder (if using), and whole sage leaves. Stir and heat gently until smooth; do not let it come to a boil.
- Preheat your oven to 400ºF (200ºC). Use a small knob of butter to grease a 9 x 13-inch baking dish well. Pour one-third of the prepared cream sauce from Step 2 into the bottom of the greased baking dish. Sprinkle a small amount of the grated parmesan cheese over the sauce. Arrange the butternut squash slices (from Step 1) in two or three overlapping rows on top of the sauce and cheese. I like to overlap the squash for an attractive, rustic look. Drizzle the remaining two-thirds of the cream sauce evenly over the squash layers.
- Cover the baking dish with a sheet of parchment paper placed directly onto the gratin's surface, then wrap with aluminum foil on top to prevent the foil from touching the food. Place the covered baking dish in the preheated oven and bake for 20 minutes. After this initial bake, remove both the foil and parchment paper, then sprinkle the remaining parmesan cheese evenly over the gratin. Return the dish to the oven and bake uncovered for another 10 minutes, or until the top is golden and crispy.
- Take the finished gratin out of the oven and let it cool slightly for a couple of minutes. Sprinkle with the chopped fresh chives for a pop of color and mild onion flavor, if desired. Serve the gratin immediately while it's warm and bubbly. For a bit of extra richness, I sometimes drizzle a small amount of browned butter over the top before serving.
