Following the packaging directions, cook the pasta and drain, reserving about 1 cup of the pasta water. Heat the olive oil in a pan over medium heat. Sauté the garlic and garlic scapes for about 5 minutes. When the scapes are tender, add the butter. Melt the butter before adding the pasta. Pour about 1/4 cup of pasta water into the pan, and toss the pasta and scapes. Season with salt and pepper. Serve with Pecorino Romano sprinkled on top.