Stuffed Zucchini

Name: Stuffed Zucchini
Prep time: 25 min
Cook time: 15 min
Total time: 40 min
Cuisine: American, Italian
Ingredients: 4 whole zucchini ((about 5 to 6 inches long)); 2 tablespoons extra-virgin olive oil (divided); 1/2 pound ground Italian turkey sausage (casings removed); 1/2 cup finely chopped red onion; 1 large red bell pepper (diced); 1/2 teaspoon kosher salt; 1/4 teaspoon ground black pepper; 1/8 teaspoon red pepper flakes; 1 teaspoon minced garlic; 2 tablespoons tomato paste; 1/4 cup packed fresh basil leaves; 2 slices whole wheat sandwich bread; 1/2 cup freshly grated Parmesan (plus additional for serving)