This spinach pie is made with eggs, caramelized onions, gruyere cheese, and golden puff pastry. An easy side dish idea for Thanksgiving or a family dinner!
Caramelize the Onions
Heat the butter in a medium saucepan over medium heat.
Cut the onions into ½ inch pieces, don’t dice too finely. They shrink down as they cook.
Heat the onions for 15 minutes, decrease the heat to medium-low, and continue to cook until they’re brown and caramelized. This takes about 35 minutes total but is worth it for the flavor. Note: If time doesn’t allow for this, use one onion instead and soften for 7 minutes.
Add the minced garlic and cook for an additional minute.
Prepare the Casserole Filling
Preheat the oven to 400 degrees.
Drain the water from the spinach.
Egg wash: Crack ONE of the eggs into a small bowl and add 1 tablespoon water. Whisk and set aside.
In a large bowl, crack the remaining 4 eggs. Whisk vigorously until well-combined. (Air pockets are created from whisking well which makes a fluffier consistency.)
Add the spinach, breadcrumbs, cheese, thyme, sage, salt, pepper, and cooked onions/garlic. Stir until well-combined.
Lightly grease a 9 x 13 inch casserole dish. Roll out one thawed puff pastry until it is large enough to cover the bottom and sides.
Add the spinach filling.
Roll out the second puff pastry sheet until it is large enough to cover the top.
Use a fork to create indentations around the edges of the casserole dish.
Brush the top of the casserole with the egg wash, don’t let it drip down the sides as that can affect rising.
Create slits on the top to allow steam to escape.
Bake for 35 minutes, or until the top is a nice golden brown.
Let it sit for 5 minutes prior to serving.
Make Ahead Method:
Mix the filling ingredients up to 2 days ahead of time and store in an airtight container until ready to bake.
Proceed with assembling the casserole with the puff pastry and bake as instructed.
Calories: 711kcal, Carbohydrates: 47g, Protein: 23g, Fat: 49g, Saturated Fat: 18g, Cholesterol: 151mg, Sodium: 635mg, Potassium: 502mg, Fiber: 5g, Sugar: 3g, Vitamin A: 11684IU, Vitamin C: 9mg, Calcium: 477mg, Iron: 5mg