Preheat your oven to 350℉ (175℃). While the oven is heating up, grease a 12-cup muffin tin to prevent the muffins from sticking. You can use butter, nonstick spray, or paper liners if you prefer.
Crack the eggs into a large mixing bowl and beat them slightly with a whisk or fork until the yolks and whites are just combined. This provides a smooth base for the batter.
Add the all-purpose flour, packed brown sugar, baking soda, pumpkin pie spice blend, ground cinnamon, sea salt, pumpkin puree, unsweetened applesauce, and milk to the beaten eggs from Step 2. Use a hand mixer to blend everything together until the mixture is smooth, but don't overmix—it’s okay if there are a few small lumps. I find that gentle mixing leads to fluffier muffins.
Evenly divide the batter from Step 3 among the 12 prepared muffin cups, filling each almost to the top. Place the muffin tin in the preheated oven and bake for about 20 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Remove the muffin tin from the oven and let the muffins cool for a few minutes. When they are cool enough to handle, carefully take them out of the tin and serve warm or at room temperature. For extra enjoyment, I sometimes spread a little butter on each muffin while they're still warm.