Bring a large pot of salted water to a boil. Cook the pasta according to package instructions until al dente, drain and set aside.

In a large skillet, heat olive oil over medium-high heat. Add the sliced Italian chicken sausage and sauté for about 5 minutes.

Reduce heat to medium-low and add minced garlic. Sauté for 30-60 seconds until fragrant.

Stir in marinara sauce, heavy cream, red pepper flakes, kosher salt, and black pepper. Let simmer for 2-3 minutes.

Add baby spinach and stir until wilted, about 1-2 minutes.

Gently fold in the drained pasta, tossing for about 2 minutes to coat with the sauce.

Serve warm, topped with grated Parmesan if desired.