Begin by bringing a large pot of salted water to a boil. Add the whole wheat penne pasta and cook according to package instructions until al dente. Drain the pasta, reserving about a cup of the pasta water for later, and set it aside.
In a large skillet, heat the olive oil over medium heat. Add the sliced red onion and minced garlic, sautéing until the onions become translucent, about 3-4 minutes.
Next, toss in the red, orange, and yellow bell peppers. Sauté for another 3-5 minutes, until the peppers start to soften. Then, add the turkey sausage rounds to the skillet, cooking until they’re browned and heated through, about 5-7 minutes.
Sprinkle in the crushed red pepper, adjusting the amount to your taste for heat. Add the halved grape tomatoes, stirring everything together until the tomatoes begin to soften, about 2-3 minutes.
Add the drained penne pasta to the skillet, tossing everything together. If the mixture seems dry, add a little reserved pasta water to create a light sauce. Season with salt and black pepper to taste.
Remove the skillet from heat and fold in the shredded Parmesan cheese and chopped fresh basil, allowing the residual heat to melt the cheese slightly.
Transfer the Spicy Sausage and Pepper Pasta to a serving bowl. Garnish with additional Parmesan and fresh basil if desired, and enjoy your vibrant, hearty meal!