Step 1

Place a rimmed baking sheet in oven; preheat oven to 425 degrees F. Toss together onion, bell peppers, fennel, oil, black pepper and salt in a large bowl.

Step 2

Arrange vegetable mixture in a single layer on preheated baking sheet. Bake in preheated oven until vegetables begin to soften, about 10 minutes.

Step 3

Remove baking sheet from oven and toss vegetable mixture. Add sausage and garlic to baking sheet. Return to oven, and bake at 425 degrees F until sausage is warmed through and vegetables are tender, about 15 minutes. Remove from oven; sprinkle with cheese, basil and crushed red pepper.