From Giada De Laurentiis's Everyday Italian Cookbook
2 C packed fresh basil leaves
1/4 C toasted pine nuts
1 garlic clove
1/2 t salt
1/4 t black pepper
2/3 C olive oil
1/2 grated Parmesan cheese
In a blender, pulse the basil, pine nuts, garlic, salt and pepper. With the blender still running, gradually add enough oil to form a smooth and thick consistently. Transfer the pesto to a bowl and stir in the cheese.
When tossing over pasta, add a little pasta water to help the pesto bind to the pasta.
When I last made this, I diced 3 tomatoes, shredded 2 carrots, and finely diced some red onion. I might have thrown in some olives as well? I can't remember.