Brussels Sprouts Gratin

Prepare Brussels Sprouts:

1. Adjust the oven rack to the middle position and heat to 450°F. Grease a 9x13-inch broiler-safe baking dish.
2. Toss Brussels sprouts with oil, ½ teaspoon kosher salt, and ¼ teaspoon ground black pepper in the baking dish. Bake until well browned and tender, about 30-35 minutes. Then, cool on a wire rack for 5 or up to 30 minutes.

Prepare Panko Topping:

1. In a medium saucepan, melt 1 tablespoon butter over medium heat. Add panko, cooking until golden, around 3 minutes. Transfer to a bowl and mix in ¼ teaspoon each of kosher salt and black pepper. Set aside.

Make Cream Sauce:

1. In the same saucepan, melt 2 tablespoons butter. Add onion and garlic, cooking until softened, about 5 minutes. Stir in flour and cook for 1 minute. Whisk in cream, water, and chicken-flavored bouillon. Bring to a boil, then remove from heat. Whisk in ¼ cup Grana Padano, Parmesan, nutmeg, cayenne, and ¼ teaspoon black pepper until smooth. Taste and adjust seasoning with salt if needed.

Assemble & Bake:

1. Pour cream mixture over Brussels sprouts in the dish, stirring to combine. Sprinkle evenly with panko mixture and remaining ¼ cup Grana Padano. Bake until bubbling and golden brown on top, 5-10 minutes. Let cool on a wire rack for about 10 minutes before serving.