Sauté the sausage: Heat olive oil in a large skillet over medium heat. Add sliced chicken sausage and cook until lightly browned, about 3–4 minutes.
Add aromatics: Stir in minced garlic and diced onion. Cook for 2–3 minutes until fragrant and translucent.
Toast the orzo: Add orzo to the skillet and stir for 1–2 minutes until slightly golden. This adds a rich, nutty flavor.
Pour in broth: Stir in chicken broth and bring to a gentle boil. Reduce heat, cover, and simmer for 8–10 minutes, stirring occasionally, until orzo is al dente.
Stir in cream and spinach: Remove the lid, pour in the heavy cream, and toss in the spinach. Stir until spinach wilts and the sauce starts to thicken.
Finish with cheese: Add shredded cheese and stir until melted and creamy. Season with salt, pepper, and red pepper flakes if using.
Serve hot: Remove from heat and let sit for a few minutes to allow the flavors to meld. Serve warm and enjoy!