Heat large pot of water with 1 teaspoon of salt until boiling. Add pasta a cook until right at al dente. Reserve 1 cup of pasta water and drain the pasta, discarding the rest of the water. Set aside.
In a large saute pan, place butter and olive oil over medium heat. Once the butter has melted, add garlic and cook until fragrant, about 1 minute. Add lemon juice and 1/2 cup of pasta water. cook until it has reduced by half. Reduce heat to low.
Add pasta to lemon sauce and toss together until pasta is warmed back up. Add lemon zest and 2 tablespoons of Pecorino cheese. Mix together slowly until cheese is incorporated. Add a little water. Once water is absorbed, add 2 more tablespoons of cheese. Repeat with a little more water until all the cheese is added. Turn off heat.
Add chopped parsley and a little more olive oil to finish it off.