Recipe: Perfect Pesto with (many) Variations

I pulled this recipe from an Herb Companion Magazine.

PERFECT PESTO
Makes 2 to 2 1/2 cups

Use pesto to season meat, poultry, and seafood, vegetables and salads, sauces, soups, salads dressings and basting mixtures. A Tablespoon will season a cup of sour cream or yogurt sauce or 2 cups of meat, salad, soup or vegetable.

1/2 cup extra-virgin olive oil and/or other oil(s)
2 or more cloves garlic, peeled and cut in several pieces
2 cups firmly packed fresh leaves and tender stems of a singe herb or a mixture of robust and mild-flavored herbs*
1/2 cup firmly packed fresh parsley leaves and tender stems
1/4 to 1/2 cup lightly toasted almonds, cashews, pecans, pine nuts, pistachios, or walnuts, or pumpkin, sesame, or sunflower seeds
1/2 cup freshly grated Parmesan, Romano, Asiago, or other hard grating cheese (optional)
Salt to taste
YOU MAY ADD OR SUBSTITUTE:
citrus zest or juice
ground seeds or spices
fresh or dried chiles
mushrooms
fresh or crystallized ginger
roasted garlic or toasted sesame oil

Process all the ingredients in a blender or food processor to the consistency of sour cream.

Store any leftovers immediately in rigid plastic freezer containers in the freezer, chipping off just what you need for each use and returning the remainder to the freezer.

*Fresh parsley mellows the flavor of tough-leaved herbs such as rosemary, savory and thyme.