Add the pesto, garlic, olives, sun-dried tomatoes and pepperoncini to a large sauce pan over low heat. Cover and cook until the pepperoncinis begin to puff up (about 15-20 minutes), stirring occasionally. Remove the pieces of garlic once the sauce is done cooking.
Cook the pasta according to package instructions. Drain the pasta, reserving 1 cup of pasta water, and add the reserved pasta water to the pesto sauce. Mix to loosen up the sauce.
Add the pasta to the sauce pan and heat until warm.
Add the salt, pepper and red pepper flakes, and mix until well incorporated. Serve!
Notes
See tips above in the blog post if you are super sensitive to spice.