In a large pot of boiling salted water, cook the cheese tortellini according to package instructions until al dente. Drain and set aside.
In a large skillet, heat olive oil over medium heat. Add the minced garlic and sauté for about 1 minute, until fragrant.
Stir in the diced tomatoes (with their juice) and heavy cream. Bring the mixture to a gentle simmer, stirring occasionally, for about 5 minutes.
Add the chopped spinach and Italian seasoning to the skillet. Cook for another 2-3 minutes, until the spinach is wilted. Season with salt and pepper to taste.
Add the cooked tortellini to the creamy tomato and spinach mixture. Gently toss to combine, allowing the tortellini to be coated in the sauce.
Stir in the grated Parmesan cheese until melted and creamy. Remove from heat.
Divide the creamy tortellini into bowls and garnish with fresh basil leaves.