Step 1

PREPARE TOPPING Adjust oven rack to middle position and heat oven to 400 degrees. Grease 13- by 9-inch baking dish. Pulse bread, ¼ cup Parmesan, and melted butter in food processor until coarsely ground. Add garlic

Step 2

MAKE FILLING Microwave broccoli florets, covered, in large bowl until bright green and tender, 2 to 4 minutes; set aside. Melt remaining butter in Dutch oven over medium heat. Cook onion and broccoli stems until softened, 8 to 10 minutes. Add rice and cook, stirring constantly, until rice is translucent, about 1 minute. Stir in broth, half-and-half, and salt and bring to boil. Reduce heat to medium-low and cook, stirring often, until rice is tender, 20 to 25 minutes. Off heat, stir in cheddar, cayenne, remaining Parmesan, and broccoli florets.

Step 3

TOP AND BAKE Pour mixture into prepared baking dish and top with bread crumb mixture. Bake until sauce is bubbling around edges and top is golden brown, about 15 minutes. Cool 5 minutes. Serve.

Step 4

MAKE AHEAD Filling can be prepared, placed in greased baking dish, covered with plastic wrap, and refrigerated for 1 day. Refrigerate topping separately. Bring filling to room temperature before adding bread crumbs and baking as directed.