Cheesy Broccoli and Cauliflower Skillet

Name: Cheesy Broccoli and Cauliflower Skillet
Ingredients: 1 small head cauliflower, cut into florets; 1 broccoli crown, cut into florets; 3 tablespoons (42 grams) unsalted butter; 1 shallot, finely diced; Kosher salt and freshly ground black pepper; 2 cloves garlic, minced; 3 tablespoons (24 grams) all-purpose flour; 2 cups (500 milliliters) milk; Pinch freshly grated nutmeg; 2 teaspoons Dijon mustard; 2 1/2 cups (288 grams) grated aged white Cheddar; 1/4 cup finely chopped chives; 1/2 cup (40 grams) panko breadcrumbs; 1/2 cup (40 grams) ground Parmesan