1) To make roasted garlic heat oven to 350 degrees Fahrenheit. Slice off the top of a head of garlic, just enough to expose the tips of the enclosed garlic cloves. Pour 1 teaspoon of olive oil into this area. Wrap the garlic in parchment paper or aluminum foil. Place the wrapped piece of garlic on a baking sheet and put in oven for 20 to 30 minutes. You can smell when it starts to get done, also you can remove from oven and gently poke sides; if its soft or squishy it's done.
2) When garlic is done and cool enough to handle, remove cloves from skins and blend all ingredients in a food processor, drizzling in oil and continuing to pulse until pesto has reached your desired texture. You may want start with 1/2 of the garlic cloves and taste before adding more. The roasted garlic taste is much more mellow than raw garlic. Another idea, if making this for pizza or as a spread, is to reserve some of the roasted garlic cloves to serve whole. Roasted garlic makes a tasty and fancy-looking spread on its own.
This freezes really well, and makes a bunch! Feel free to cut down on amounts, or do what I do and freeze so you always have pesto on hand. Use on pizzas, foccica, pasta, on roasted potatoes, etc....Yum!
Source of recipe: I wrote this recipe