Step 3
Return reserved skillet to medium heat. Add oil, onion, and bell pepper. Season with salt and pepper. Cook, stirring occasionally, until tender, 8 to 10 minutes. Stir in garlic, fennel seeds, and red pepper flakes. Cook, until fragrant, 1 minute. Add wine and simmer until thickened, 3 to 5 minutes. Add tomatoes and cooked sausage to skillet; toss to combine.