WOW Spinach Gratin

 

4 T. unsalted butter

2 medium-sized yellow onions, chopped

1/4 C. unbleached flour

3 C. organic whole milk (I heated it in the microwave for 45 seconds)

1/4 tsp. freshly grated nutmeg

a few pinches of cayenne

1 1/2 C. grated Gruyere cheese

3 16 oz. bags of organic, chopped spinach – thawed

1 tsp. kosher salt

1/2 tsp. ground pepper

Panko breadcrumb topping:

2 T. unsalted butter

1 1/2 C. panko breadcrumbs

sea salt, to taste

 

Squeeze the liquid from the thawed spinach, handful by handful. Set aside. Heat milk to simmer in saucepan (I used the microwave).Melt the). Meltr in a heavy-bottomed pot. Add onions and cook until wilted but not browned, for about 7 minutes. Add the flour and cook for 2 minutes. Stir in the hot milk and whisk the sauce until it thickens. Add nutmeg and cayenne. Turn off the heat. Stir in the cheese and season with salt and pepper. Taste and correct seasoning. Add the spinach and mix well. Pour into a greased 9×11 glass or ceramic baking dish. Prepare crumb topping. Melt butter in medium skillet. Add panko, sprinkle with sea salt and stir until lightly toasted. This happens quickly, so make sure you don’t burn the crumbs. Gently smooth the toasted panko on top of the gratin. Bake for 25-30 minutes at 375F until bubbling.