Begin to boil the pasta water in a large stockpot and cook according to package directions.
Melt butter in a separate large pot over medium-high heat and saute the onions and garlic until softened, which takes about 4-5 minutes.
Add tomatoes to the pot and stir. Slowly add the vodka, the milk or non-dairy milk, lemon juice, and lemon zest, stirring gently as you add each ingredient.
Bring heat to high and bring the water to a boil, then lower heat to low-medium and simmer for about 5 minutes.
Add shrimp to the sauce. If you are using raw shrimp, you'll need to cook it in the simmering pasta sauce for another 5-7 minutes, until it's just cooked. If you are using thawed, fully cooked shrimp, you'll just need to let it heat up and mix in with the sauce for about 3 minutes.
Add the cooked pasta to the sauce and gently fold the pasta into sauce until it's nicely covered in sauce.
Salt and pepper to taste. Garnish with freshly chopped parsley and/or freshly grated parmesan cheese.