Lemony Shrimp and Spinach Linguine

This is SO easy to make. I literally made it from start to finish in 15 minutes. I served it with the Simple Salad with Lemon Vinaigrette. There is no butter in it, so it's low in saturated fat and the leftovers were awesome! The original recipe was called Linguine with Shrimp and Lemon Oil. I found that it really wasn't necessary to make the lemon oil and I substituted spinach for the arugula, since I always have it on hand. You can also leave the shrimp out and add in roasted red bell peppers for a vegetarian version.

1 box linguini pasta (you can use whole wheat, but I actually prefer white in this recipe)
1/3 cup plus 2 tbsp olive oil, divided
1/2 cup red onion, finely diced
2 garlic cloves, minced
1 16 oz bag frozen cleaned and peeled shrimp
1/4 cup lemon juice (2 lemons)
2 lemons, zested
1 tsp salt
1/2 tsp pepper
3 handfuls of baby spinach
1/4 cup chopped flat leaf parsley
1/2 cup shredded parmesan cheese (you can buy it in a bag in the shredded cheese section) plus more for topping each individual serving

Heat the 2 tbsp of olive oil in a skillet. Sautee the red onion and garlic until tender and translucent. Add the shrimp, salt and pepper. Cook until the shrimp are thawed and just turning pink. Add the lemon juice, lemon zest, 1/3 cup olive oil, spinach and parsley. Mix well. Toss in the pasta and the 1/2 cup parmesan cheese. Top each indivdual serving with more parmesan and freshly grated pepper, if desired.