White Pesto Pasta

Ingredients (10)

• 3/4 cup walnuts
• 2 tsp finely chopped oregano
• 1 garlic clove
• 1 lemon
• 1 cup fresh ricotta
• 2 oz finely grated Parmesan
• 1/8 tsp salt
• 1/8 tsp red pepper flakes
• 1/2 cup extra-virgin olive oil
• 1 lb rigatoni