Step 1

Position a rack in middle of oven. Preheat oven to 425°F.

Step 2

Combine fennel, red and green peppers, potatoes, onion, and garlic in a large bowl. In a small bowl, combine oil, vinegar, mustard, salt, pepper, and red pepper flakes; stir until well combined. Add oil mixture to vegetables; toss to combine. Add sausage; toss to combine. Transfer to a 9- X 13-inch casserole dish.

Step 3

Roast, covered, 15 minutes. Uncover, roast, 10 minutes more. Remove from oven and sprinkle evenly with cheese; roast until fennel and potatoes are tender and browning a bit, about 5 minutes more. Garnish with chopped fennel fronds; serve.

Step 4

Serving size: about 2 cups