An Authentic Pesto Recipe

12 walnuts, shelled
2 tablespoons pine nuts
1 teaspoon coarse salt
4 to 5 black peppercorns
3 garlic cloves
4 tablespoons butter
3 cups basil leaves
4 ounces grated Parmesan cheese
4 ounces grated Romano cheese

Place all ingredients except 1 cup olive oil in food processor and
grind very fine. Add remaining olive oil and blend a few seconds until
very smooth.