Pasta Puttanesca with Spinach

Put a pot of water on to boil. Heat olive oil on medium high heat in a largue sauté pan. Add onion and sauté until translucent, about 4 minutes. Add garlic and cook until very lightly browned, about 2 minutes. Add olives, capers, and anchovy paste and stir until anchovy paste dissolves into mixture. Add tomatoes, tomato sauce, red pepper flakes, and oregano. Turn heat down to medium low and let simmer while pasta cooks.

Cook the pasta to al dente according to package instructions. Drain, reserving 1/4-1/2 cup pasta water. Add spinach (from frozen is fine) to the sauce and bring back to a simmer. Add pasta and some of the pasta water (enough so that the sauce really sticks to the pasta). Stir. Serve pasta topped with parmesan cheese and crusty bread.