How to Make It
Preheat oven to 350°F. Prepare pasta according to package directions for al dente.
Melt 6 Tbsp. butter in a large saucepan over medium. Add next 6 ingredients; cook, stirring, 30 seconds. Add flour, and cook, stirring, until golden, 2 minutes. Gradually whisk in milk and cream. Bring to a boil, whisking occasionally. Reduce heat to medium-low; simmer, whisking, until slightly thickened, 5 minutes. Stir in Worcestershire sauce. Remove from heat; stir in shredded and diced cheeses until melted. Stir in pasta; pour into a lightly greased 13- x 9-inch (3-quart) baking dish. Stir together panko, melted butter, sage, thyme, and rosemary; sprinkle over casserole before baking.
Bake on a rimmed baking sheet in preheated oven until bubbly and golden, 30 minutes or until topping is golden brown. Remove from oven; cool slightly on a wire rack, about 15 minutes.
Make it ahead: Prepare through Step 2 up to 1 day in advance; cover and refrigerate. Bring to room temperature before proceeding with Step 3.