Cheesy Spinach Bake

Preparation

1. Step 1

   Heat the oven to 400 degrees. In a large, ovenproof skillet, melt the butter over medium. Spoon out 1 tablespoon of the butter into a medium bowl. To the skillet, add the onion and garlic, season with salt and pepper, and cook, stirring occasionally, until softened but not browned, 7 to 10 minutes.

2. Step 2

   While the onions are sautéing, stir the bread crumbs into the bowl of butter until coated, season with salt and pepper, then stir in half the Parmesan.

3. Step 3

   Add the spinach to the skillet and stir until warm and dry, perhaps even sticking to the skillet, 2 to 4 minutes. Turn off the heat. Stir in the half-and-half, remaining Parmesan and the nutmeg (if using), then taste and adjust seasonings with salt and pepper. (If you’d like to bake this dish in a 2 ½-quart or larger casserole dish rather than directly in the skillet, transfer the spinach now.)

4. Step 4

   Top evenly with the Gruyère, then the panko mixture. Bake until golden on top and bubbling around the edges, 20 to 25 minutes.