Heat olive oil over medium heat.
Add pesto and mix into the oil. Be sure to stir often as the pesto warms.
When the pesto is warmed and just a little bubbly, slowly stream in the heavy cream as you stir. (You can always add more cream if you'd like.)
Add some pasta water to thin out the sauce, if needed.
Turn down the heat and continue to stir to incorporate the cream and pesto.
Salt and pepper to taste.
