01 - Bring a large pot of salted water to a rolling boil. Cook the cheese tortellini according to package directions until al dente. Drain thoroughly and set aside.
02 - While the tortellini cooks, season the diced chicken breasts evenly with salt, pepper, and Italian seasoning. Heat olive oil in a large skillet over medium-high heat. Add the chicken and sear until golden brown and cooked through, approximately 5 to 7 minutes. Remove the chicken from the skillet and set aside.
03 - In the same skillet, melt the butter over medium heat. Add the chopped onion and sauté for 2 to 3 minutes until softened. Stir in the minced garlic and cook for 1 minute until fragrant.
04 - Pour in the chicken broth and deglaze the skillet, scraping up any browned bits from the bottom. Reduce the heat to medium and add the heavy cream along with the Parmesan cheese. Stir continuously until the cheese has melted and the sauce thickens slightly, about 3 minutes.
05 - Add the fresh baby spinach to the skillet and stir gently until wilted, approximately 1 to 2 minutes.
06 - Return the seared chicken to the skillet along with the cooked tortellini. Gently toss everything together until evenly coated in the creamy garlic sauce. Adjust seasoning with additional salt and pepper to taste. Serve immediately, garnished with extra Parmesan and chopped fresh parsley if desired.