Preheat oven to 375°. Place brussels sprouts on baking sheet and toss with olive oil. Season with salt and pepper then bake until tender, about 30 minutes.
In a large saucepan over medium heat, melt butter. Sprinkle over flour and cook until slightly golden, 2-3 minutes. Pour in milk and whisk until combined. Season with salt and pepper. Let simmer until starting to thicken, about 5 minutes.
Remove pan from heat and stir in cheddar, fontina, and ½ c parmesan and whisk until smooth. Fold in cooked pasta and cooked brussels sprouts. Transfer into baking dish.
In a medium bowl, combine Panko and the remaining parmesan. Season with salt and pepper and sprinkle over pasta.
Bake until bubbly and golden, 25-30 minutes. Serve.
Recipe by Cooking TV Recipes at https://cookingtv-channel.com/brussels-sprouts-mac/