Skillet Cauliflower Mac and Cheese

Name: Skillet Cauliflower Mac and Cheese
Ingredients: 1 (1-lb.) pkg. cavatappi pasta; 1 pound cauliflower florets (about 5 cups) (from 1 medium head); 1/4 cup olive oil, divided; 2 teaspoons kosher salt, divided; 3/4 teaspoon black pepper, divided; 2 tablespoons water; 1/3 cup (2 2/3 oz.) unsalted butter; 1/3 cup (about 1 1/2 oz.) all-purpose flour; 4 cups whole milk, warmed; 8 ounces extra-sharp white Cheddar cheese, shredded (about 2 cups); 8 ounces Gouda cheese, shredded (about 2 cups); 1 teaspoon Mexican-style hot sauce (such as Cholula); 3/4 cup panko (Japanese-style breadcrumbs); 1/4 cup finely chopped scallions (from 3 scallions)