1. Bring a large pot of salted water to a rolling boil. Add the fresh or frozen cheese tortellini and cook according to package directions until al dente. This usually takes about 2-4 minutes for fresh tortellini and 5-7 minutes for frozen.

2. Once the tortellini is cooked, drain it well using a colander. Before discarding all the water, reserve about 1/2 cup of the starchy pasta water. This will be useful later to adjust the sauce consistency if needed.

3. While the tortellini is cooking, heat the olive oil in a large skillet or pan over medium heat. You don’t want it smoking, just warm enough to gently heat the pesto.

4. Reduce the heat to low. Add the basil pesto to the skillet and stir for about 30 seconds to warm it through. Pour in the heavy cream and stir continuously until the sauce is smooth and gently simmering. It should thicken slightly.

5. Stir in the grated Parmesan cheese until it melts into the sauce, making it even creamier. Season the sauce with salt and black pepper to taste. Remember that pesto and Parmesan can be salty, so taste before adding too much.

6. Add the drained tortellini directly into the skillet with the creamy pesto sauce. Gently toss everything together until the tortellini is evenly coated in the sauce. If the sauce seems too thick, add a tablespoon or two of the reserved pasta water until it reaches your desired consistency.

7. Transfer the creamy pesto tortellini to serving plates. Garnish with a sprinkle of extra grated Parmesan cheese and a few fresh basil leaves, if desired. Serve hot and enjoy!