Cook the rotini pasta according to the package instructions until al dente. Drain and set aside.
In a large skillet, heat the olive oil over medium heat. Add the diced onion and sauté until translucent, about 5 minutes.
Add the minced garlic to the skillet and cook for an additional minute until fragrant.
Add the sliced apple Gouda sausage to the skillet. Cook, stirring occasionally, until the sausage is browned, about 5-7 minutes.
Add the diced apples to the skillet and continue to cook until they are tender, about 3-4 minutes.
Reduce the heat to low and pour in the heavy cream, stirring to combine. Allow the mixture to simmer for 2-3 minutes.
Stir in the shredded Gouda cheese, salt, and black pepper until the cheese has melted and the sauce is smooth.
Add the cooked pasta to the skillet and toss until everything is well combined and the pasta is coated with the sauce.
Sprinkle the fresh thyme leaves and chopped parsley over the top of the pasta, stirring gently to mix.
Serve the pasta hot, garnished with additional fresh parsley if desired.