Add the olive oil, lemon juice, garlic and pine nuts to your blender. Add the cheese, salt, pepper and basil leaves.
Tightly seal the lid and blend until smooth, about 30 seconds. If necessary, stop the blender and scrape down the sides with a silicone spatula halfway through.
Cook Tortellini ONE of two ways:
Instant Pot Cooking Instructions
Add tortellini to the pressure cooker pot. Add 2 cups water along with ½ teaspoon kosher salt and close the lid.
Cook on pressure cook or Manual at high pressure for 3 minutes. When pressure cooking is complete, perform an Intermittent Quick Release, which means release pressure in bursts. Open the lid once the pin drops.
Reserve about ½ cup starchy cooking water, then drain the pasta and transfer it to a large serving bowl.
Bring a large pot of water to a boil and liberally season with salt. Add the tortellini and cook according to the package directions until al dente, or with a slight bite in the center. Reserve about ½ cup starchy cooking water, then drain the pasta and transfer it to a large serving bowl.
Assemble Perto Tortellini
Add pesto to the bowl. Using two large serving spoons toss the tortellini in pesto, adding a few tablespoons of the starchy cooking water until the tortellini gets coated with the pesto sauce.
Do not heat the pesto. This will ruin the flavor, color and texture of your finished sauce. The residual heat from the cooked tortellini will be enough to heat the pesto through.
Reserve about ½ cup of the pasta cooking water. This is the secret many Italian chefs use when cooking any pasta entree. A few tablespoons of the starchy cooking water not only helps thin out the pesto sauce, but if stirred vigorously for 1-2 minutes, the starch naturally emulsifies with the sauce, creating a luxurious, creamy consistency.
Release Pressure by performing an Intermittent Quick Release: To prevent the starchy pasta water from spraying through the pressure knob, I release the pressure in bursts. Which means, I press the pressure knob gently to release pressure 1-2 seconds at a time, then stop. I repeat this until most of the pressure has released and its intensity has gone down. After that, when I do a full release of pressure, nothing squirts out of the knob.
Wash the lid and clean the pressure valve of the Instant Pot after cooking the pasta. Since the pasta starch and scum may have caused a blockage in the Instant Pot, this could affect the next cooking cycle. Make sure to wash it out with warm, soapy water.
To prepare this recipe for meal prep, you can prepare the pesto and cook the tortellini ahead of time and store them separately in the refrigerator. When ready to eat, you can warm the tortellini in the microwave for a minute, along with a few tablespoons of water, then toss the pesto with it. Alternatively, you can skip warming it and eat it cold.
Note: The nutrition facts below are my estimates for 12 ounces of cheese tortellini. If you are following any diet plan, I recommend cross-checking with your preferred nutrition calculator.