A topping of cheese sauce and buttery bread crumbs transforms everyday vegetables into a special occasion treat. While any melting cheese like cheddar or Swiss will work, nutty-tasting Gruyère is an especially good match for the broccoli and cauliflower.

 
5 cups cauliflower florets (about 2 lb.)
5 cups broccoli florets (about 1 3/4 lb.)
2 cups whole milk
1/4 cup plus 1 tablespoon butter, divided
1/3 cup all-purpose flour
2 teaspoons dry mustard
3/4 teaspoon salt
1/4 teaspoon black pepper
Dash cayenne pepper
1/2 cup panko*
2 cups shredded Gruyère, Comté or Manchego cheese, divided
 
1 Heat oven to 425ºF. Spray 13x9-inch glass or ceramic baking dish with cooking spray.
 
2 Cook cauliflower in large pot of boiling salted water 3 minutes or until almost tender. With slotted spoon, place in large bowl of ice water to stop cooking. Add broccoli to boiling water; cook 2 minutes or until almost tender. Place in ice water. Drain cauliflower and broccoli well; pat dry. Place in baking dish. 
 
3 Microwave milk in 4-cup glass measuring cup 2 to 3 minutes or until steaming hot but not boiling. Melt 1/4 cup of the butter in large saucepan over medium heat; whisk in flour until smooth. Cook 30 seconds, whisking constantly. Remove from heat; gradually whisk in hot milk. 
 
4 Return saucepan to medium-high heat; bring to a boil, whisking constantly. Reduce heat to low; simmer 5 minutes or until thick, whisking occasionally. Remove from heat; whisk in mustard, salt, black pepper and cayenne pepper.
 
5 Microwave remaining 1 tablespoon butter in small microwave-safe bowl until melted; stir in panko. Sprinkle cauliflower and broccoli with 1 cup of the cheese; top with sauce. Sprinkle with remaining 1 cup cheese; top with panko mixture. (Gratin can be made to this point 2 days ahead. Cover and refrigerate. Add 5 to 10 minutes to baking time.)
 
6 Bake, uncovered, 30 to 40 minutes or until golden brown and bubbly.
 
8 servings
 
PER SERVING: 305 calories, 19 g total fat (11 g saturated fat), 15.5 g protein, 21.5 g carbohydrate, 55 mg cholesterol, 1040 mg sodium, 6 g fiber 
 
TIP *Panko are coarse bread crumbs usually found next to other bread crumbs in the supermarket.