Spinach & Tomato Pesto Pasta

I got this recipe from a ward recipe exchange. The original recipe calls for a pound of chicken, grilled and cubed, but it tasted great without as well. I'm always on the lookout for good pasta recipes, and this one is surprisingly zesty and full of flavor!

12 to 16 oz. pasta
1 jar Classico Traditional Basil Pesto (or 1 cup of homemade pesto)
4 Tbsp. lemon juice
1/2 bag of fresh spinach, shredded
2 medium roma tomatoes, chopped
1/4 c. red onion, diced (optional)

Prepare pasta as directed on package. Rinse in cold water. Mix Classico pesto sauce in to taste with lemon juice. Add chicken (if using), spinach, tomatoes, and onion and toss. Serve with powdered parmesan cheese.