Cook the tortellini according to the package directions.
While the tortellini cooks, make the pesto.
Place the sun-dried tomatoes (remove from the oil), pine nuts, garlic, basil, parmesan, salt and pepper in the bowl of a food processor and pulse until all ingredients roughly chopped.
Using a rubber spatula, scrape down the sides of the bowl and replace the lid
With the machine running on low, slowly stream in the olive oil and process until just combined but still kind of chunky.
Stir in 1 tablespoon of the reserved sun-dried tomato oil from the jar.
Drain the tortellini and return to the pot.
Spoon 1/2 of the pesto over the tortellini and toss gently to coat. (If you want it to be coated more, you can use all the pesto.)
Serve with parmesan cheese and chopped fresh basil, if desired.
Leftover pesto can be stored in the refrigerator for up to 5 days in an airtight container.
The sun-dried tomato pesto can be made up to 10 days in advance and stored in an airtight container.Leftover pasta can be stored in an airtight container for up to 3 days. Reheat either in a saucepan with a bit of olive oil or in the microwave.