Heat the olive oil, butter, garlic and crushed red pepper in a large skillet, over medium heat, stirring occasionally until the garlic is fragrant, about 2 minutes. Add the wine, clam broth and the cleaned clams and simmer, stirring occasionally for 8-10 minutes. The clams will open, however if they don't, toss them. Add the cooked pasta to the skillet and stir until reheated. For a smoother sauce, you can add some of the reserved pasta water. Add salt and black pepper, to taste. Serve the dish with the chopped parsley and a squeeze of fresh lemon juice.