Bring a large pot of salted water to a boil. Add the penne pasta and cook according to package instructions until al dente, about 10-12 minutes. Drain and set aside.
While the pasta cooks, heat olive oil in a large skillet over medium heat.
Add the chopped onion to the skillet and sauté until translucent, about 4-5 minutes.
Add the minced garlic and cook for 1 minute until fragrant.
Add the ground turkey to the skillet. Cook, breaking it up with a spoon, until browned and cooked through, about 6-8 minutes.
Stir in the crushed tomatoes, dried oregano, dried basil, salt, black pepper, and red pepper flakes. Bring the sauce to a simmer and cook for 10 minutes, stirring occasionally.
Add the cooked pasta to the skillet with the sauce and toss to combine thoroughly.
Remove from heat and stir in the grated Parmesan cheese.
Garnish with chopped fresh parsley before serving.