The fluffy goodness that is spinach soufflé often contains gluten. But not with this lip-smacking recipe. Rice flour makes the rich, delicious dish accessible to all, without compromising flavor. It makes great leftovers, too, if you're lucky enough to have some remaining at the end of the meal.
Melt the 2 tablespoons butter in a skillet over medium heat. Whisk in the flour until it’s fully incorporated and smells a bit nutty, but has not taken on any color, about 3 minutes. Whisk in the warmed milk and cook, whisking, until the mixture starts to thicken and coat the back of a spoon, 6 to 8 minutes. Stir in the nutmeg, salt, and white pepper. Remove from the heat. Gradually add the Gruyère in batches, whisking in each batch to incorporate before adding more. Gradually whisk in 1/4 cup of the Parmesan cheese. Whisk in the egg yolks, then stir in the spinach. Set aside.