Spaghetti With Spring Pesto

Ingredients

• 4 cups trimmed watercress (about 1 bunch)
• 1 1/2 cups fresh parsley
• 1 cup basil leaves
• 1/2 cup pecan halves
• 1/2 cup frozen green peas, thawed
• 1/2 cup fat-free ricotta cheese
• 1/4 cup (1 ounce) grated fresh Parmesan cheese
• 1/3 cup (1-inch) sliced green onions
• 1/2 teaspoon salt
• 1/4 teaspoon pepper
• 3 garlic cloves
• 1 1/2 tablespoons olive oil
• 6 cups hot cooked spaghetti (about 1 pound uncooked pasta)