Cremini and Spinach Cheesy Ditalini Skillet

1. Stage

Bring a large pot of lightly salted water to a boil. Cook ditalini in the boiling water, stirring occasionally, until not quite done, about 9 minutes (it will continue to cook in the oven.) Strain and set aside.

2. Stage

In the meantime, melt butter in a 12-inch cast iron skillet over medium heat. Add pepper flakes and garlic powder; let bubble for about 1 minute. Add onion, shallots, and a good pinch of salt and pepper; cook and stir until onion is translucent, about 5 minutes. Add mushrooms, thyme sprigs, and another generous pinch of salt and pepper; cook for 3 more minutes.

3. Stage

Add spinach and another pinch of salt; cover and cook until spinach has wilted, 2 to 3 minutes. Add flour and mustard powder; stir until it has been fully absorbed. Cook and stir for 1 more minute.

4. Stage

Slowly pour in milk, making sure to scrape the bottom for any crusty bits; continue until all of the milk has been absorbed. Bring to a boil. Reduce heat to medium-low and continue to stir until the rapid bubbling stops. Cover and simmer for 10 minutes.

5. Stage

Preheat the oven to 375 degrees F (190 degrees C).

6. Stage

Remove the sauce from the heat. Pluck out and discard the thyme sprigs. Stir in Cheddar and mozzarella cheeses. Fold in cooked ditalini until everything is nice and combined.

7. Stage

Whisk bread crumbs, garlic, 1 tablespoon Grana Padana cheese, thyme leaves, and a good pinch of salt and pepper for topping together in a bowl. Add 1 tablespoon olive oil at a time, working it into the crumbs until they are moistened and crumbly. Sprinkle over the skillet.

8. Stage

Bake in the preheated oven until bubbly and golden on top, 20 to 25 minutes. Remove from the oven and set on a wire rack.