Cook the Pasta: Bring a large pot of salted water to a boil. Add the penne pasta and cook according to package instructions until al dente. Drain and set aside, reserving 1/2 cup of pasta cooking water.
Cook the Sausage: In a large skillet, heat olive oil over medium heat. Add the sausage and cook, breaking it apart with a spatula, until browned and cooked through, about 5-7 minutes.
Make the Sauce: In the same skillet, push the sausage to one side and add the minced garlic. Sauté for about 1 minute until fragrant, then mix it with the sausage.
Add Honey and Soy Sauce: Drizzle honey and soy sauce over the sausage and garlic. Sprinkle in red pepper flakes if using, then stir everything together to coat the sausage in the sauce. Cook for an additional 2-3 minutes until the sauce thickens slightly.
Combine with Pasta: Add the cooked pasta to the skillet, tossing to combine with the sausage and sauce. If the pasta seems dry, add a bit of the reserved pasta cooking water until desired consistency is reached. Season with salt and pepper to taste.
Finish and Serve: Remove from heat and stir in chopped parsley. Serve immediately topped with grated Parmesan cheese.