Ravioli with Spinach and Sundried Tomatoes

Name: Ravioli with Spinach and Sundried Tomatoes
Ingredients: 20 ounces cheese ravioli; 6 - 9 oz. baby spinach; 1 tbsp. extra virgin olive oil; 1/2 yellow onion finely diced; 1 teaspoon minced garlic (1 – 2 cloves); 5 sundried tomatoes marinated in oil or dry, chopped; 1/4 - ½ tsp. crushed red pepper flakes to taste (optional); 1 ½ cups red pasta sauce