Bring a pot of water to a boil, add salt and cook pasta al dente. Reserve 1/2 cup pasta water before draining.
While pasta is boiling, melt butter with a splash of cooking oil in a pan on medium heat, add shrimp with a dash of salt and pepper, and cook 2 minutes per side. Remove from pan and set aside.
Reduce heat to medium-low, and in the same pan, add another splash of oil if needed, garlic, and chili flakes.
Simmer for about 1 minute, or until garlic becomes fragrant.
Add smoked salmon and zest from 1 lemon to the pan. Cook for a couple of minutes or until salmon becomes pale.
Add heavy cream, a splash of lemon juice, chili flakes, a big pinch of salt and pepper, and simmer for 1 minute.
Add 1/4 cup pasta water, parmesan, and farfalle. Mix and add shrimp back to the pan and simmer until some of the water is absorbed by the pasta and the sauce becomes creamy. Mix in the rest of the pasta water if the sauce is too dry.
Top with parsley and plate.