Cook the tortellini according to packages directions for al dente. Reserve 1 cup of pasta water in case you need to thin the sauce. Drain well and return to the pot.
Over low heat, toss together the pesto sauce with pine nuts and half of the asiago cheese. If needed, add a small amount of pasta water to thin the pesto.
When warmed through, transfer to serving dishes and top with additional asiago cheese and crushed red pepper flakes, if desired.
If you've tried this recipe, come back and let us know how it was in the comments or ratings section.