Heat olive oil in a frying pan and add sliced mushrooms.

Cook mushrooms until they turn golden brown.

Add basil pesto sauce to the pan.

Add diced onions to the pan and mix well.

Continue to sauté the mixture until well combined. The pasta sauce is ready!

Boil pasta in salted water according to package instructions.

Drain the cooked pasta and set aside.

Combine the cooked pasta with the prepared sauce in the pan.