The Pesto recipe I follow is pretty basic, but the trick is to let it sit for an hour or more after you make it, then blend it again later. It turns the pesto into a creamy green butter-like spread.

2 cups fresh basil leaves
⅓ cup pine nuts
3 large cloves garlic
½ cup extra-virgin olive oil
½ cup freshly grated parmesan cheese
salt & pepper to taste

Put it all in the food processor and blend the heck out it. Then let it sit for an hour or more. Then blend the heck out of it again. Enjoy!