Prepare all the ingredients before you begin cooking. Grate the Parmesan, mince the garlic, dice the shallot, roughly chop the basil, and chop the drained sun-dried tomatoes.
Melt the butter in a large, deep skillet or pot over medium-low heat. Add the garlic and shallot and sauté for about 3 minutes, stirring frequently, until softened and fragrant.
Add the black pepper, chili flakes, dried thyme, and tomato paste. Stir well and cook for another 2 minutes to deepen the flavor of the tomato paste.
Add the cheese tortellini and pour in the vegetable broth. Bring the mixture to a gentle boil, then reduce to a simmer and cook for about 3 minutes, or according to the tortellini package directions.
Pour in the heavy cream and simmer for 1 minute. Reduce the heat and stir in the Parmesan until melted and the sauce becomes smooth and creamy.
Add the sun-dried tomatoes and fresh basil. Gently stir until everything is evenly coated in the creamy sauce.
Serve the One-Pot Marry Me Tortellini immediately with freshly ground black pepper and additional chili flakes if desired.