In a large pot, boil salted water and cook the pasta as directed on the box. Drain and set aside.
Meanwhile, heat a large sauté pan to medium-high heat. Add the oil and butter. Sprinkle the shrimp with flour before adding them to the skillet. Once melted, add the garlic and shrimp.
Cook the shrimp for one minute, then add the wine and cream. Toss and cook another minute, then add olives and tomatoes. Simmer another 1-2 minutes.
Finally, mix in the strained pasta and spinach leaves. Remove the skillet from the heat once the spinach wilts. Salt and pepper to taste. (Season carefully, the olives and feta add a lot of salt.) Divide onto plates and top with feta cheese.