Preheat your oven to 375°F (190°C). Lightly oil a 9 x 13-inch baking dish or coat it with nonstick spray to prevent the croissants from sticking when baking.

In a small bowl, combine the room temperature unsalted butter, Dijon mustard, finely chopped green onions, and honey. Season the mixture with sea salt and black pepper to taste, stirring until well mixed. I like to taste a little of the spread at this stage to ensure it’s well balanced and add a tiny pinch of salt if needed.

Slice each croissant open and generously spread the prepared butter mixture (from Step 2) on both the top and bottom halves. Layer thinly sliced smoked deli ham and a slice of Swiss cheese onto each croissant, then close to form sandwiches. Arrange the filled croissants in a single layer in the prepared baking dish.

In a small bowl, whisk the egg white with 1 tablespoon of water to make an egg wash. Brush the tops of each croissant sandwich with this mixture. Sprinkle the poppy seeds evenly over the croissants for a nice crunch and added flavor.

Place the baking dish in the preheated oven and bake for 15-18 minutes, or until the croissants are golden brown and toasted. Let them stand for about 5 minutes before serving warm. For an extra touch, I sometimes serve these with a little grainy mustard or pickles on the side.