Prepare your pasta according to the package directions.
While it cooks, melt two tablespoons of butter in a large saute pan over medium heat. When it’s melted, add in the onion and mushrooms, and saute until the onion is cooked through. (If the veggies soak up all the butter, you might add a tablespoon or two more to make sure there’s a little fat in the pan for the next step.)
Stir in the little bit of flour and add the garlic, sauteing until the garlic just becomes fragrant and the flour is all absorbed.
Stir in the cream, lemon juice, basil, oregano, parsley and sun-dried tomatoes, being sure to incorporate any browned bits stuck to the bottom of the skillet.
Let the mixture come to a low simmer, and let it cook for two minutes.
Add the shrimp, letting them cook in the sauce for about five minutes or until they’re cooked through.
Finally, stir in the pasta and spinach, stirring to wilt the spinach into the sauce, and add salt and pepper to taste.