It is similar to the creamed corn served at Lawry's Prime Rib in Beverly Hillsand Beckham's Place in Pasadena.
Foodfan, you can't go wrong with anything that tastes like those...thanks for the recipe.
This has become a Thanksgiving standard for me, and you can assemble it well ahead of turkey day. I added some of my Notes following the recipe.
(recipe from Ina Garten)
4 T. (1/2 stick) butter
4 cups chopped yellow onions
1/4 cup flour
1/4 tsp. nutmeg
1 cup heavy cream
2 cups milk
5 10-oz. pkgs. frozen chopped spinach, defrosted, and squeezed dry (use your potato ricer!)
1 cup freshly grated Parmesan cheese, divided
1 T. kosher salt, or to taste
1/2 tsp. freshly ground black pepper
1/2 cup grated Gruyere cheese
Preheat the oven to 425.
Melt the butter in a heavy-bottomed saute pan over medium heat. Add the onions and saute until translucent, about 15 minutes. Add the flour and nutmeg and cook, stirring, for 2 more minutes. Add the cream and milk and cook until thickened. Add the spinach to the sauce. Add 1/2 cup of the Parmesan cheese and mix well. Season to taste with the salt and pepper.
Transfer the spinach to a buttered baking dish and sprinkle the remaining 1/2 cup Parmesan and the Gruyere on top. (If making ahead, don't put Parmesan and Gruyere on top until ready to bake.) Bake for about 25 minutes or until hot and bubbly.
*Note: I use a litle less onion, probably a scant 3 cups. I buy 3 bags of the 16-oz. frozen chopped spinach at Trader Joe's. Typical of Ina Garten, it sounds like a lot of salt. However, the white sauce and spinach need the seasoning, even with the Parmesan. Try adding less salt first (a couple teaspoons) and see what you think. You can assemble this a couple days ahead, cover and chill. Bring to room temp before baking. I use an oval gratin/casserole dish for this that measures 12x9x2.