10 oz package frozen chopped spinach
¼ cup finely minced yellow onion
4 tablespoons (1/2 stick) butter
3 tablespoons all-purpose flour
½ teaspoon salt
Pinch of cayenne pepper
¼ teaspoon black pepper
1 cup whole milk
1 cup (1/4 pound) grated Swiss cheese
½ cup freshly grated Parmesan cheese
3 eggs, beaten well
Optional – handful of cherry tomatoes, sliced
- Preheat the oven to 325 degrees. Spray a 1 ½-quart casserole with vegetable oil cooking spray
- Remove the spinach from the packaging and transfer to a microwave-safe bowl. Microwave on high for 2 minutes. Remove the spinach and squeeze dry with your hands. Place the spinach into a medium mixing bowl.
- In a skillet, over medium low heat, sauté the onion in 1 tablespoon of the butter until soft, about 3-4 minutes. Add the onion to the spinach.
- In the same skillet, melt the remaining 3 tablespoons butter over medium low heat. Whisk in the flour, salt, cayenne pepper, and black pepper. Stir until smooth. Slowly add the milk and continue stirring until the mixture thickens, 3 to 5 minutes. Turn off the heat. Stir in the Swiss and Parmesan cheeses and continue stirring until the mixture is smoother. Pour the sauce over the spinach in the mixing bowl. Add the eggs and stir well.
- Pour the spinach mixture into the casserole. (top with sliced tomatoes if desired) Place the casserole into a larger casserole dish filled with 1 inch of water (a hot water bath) and bake for 45 minutes.