Start by bringing a large pot of salted water to a rolling boil. Add the cheese tortellini and cook according to package instructions, about 3–4 minutes for fresh or 6–7 minutes for frozen. Drain, reserving 1 cup of pasta water.

In a large skillet, melt 1 tablespoon of unsalted butter over medium-high heat. Season the shrimp with salt, pepper, and Italian seasoning. Add the shrimp to the skillet and sauté for 2–3 minutes per side until pink and opaque. Transfer to a plate.

In the same skillet, reduce heat to medium and add the remaining tablespoon of butter. Once melted, add the minced garlic and sauté for about 1 minute until fragrant.

Pour in the heavy cream and simmer gently for 3–5 minutes until thickened. Stir constantly, ensuring it doesn't boil over.

Stir in the Parmesan cheese until melted completely. If using fresh spinach, fold it into the sauce until wilted.

Add the cooked tortellini to the sauce, coating well. If the sauce is too thick, add a bit of reserved pasta water.

Return the sautéed shrimp to the skillet, mixing gently. Heat through and serve hot.