Bring a large pot of salted water to a boil and cook pasta till al dente. Drain and cover.
Brown pancetta over medium high heat, about 8 minutes.
Melt butter over medium heat, add onions and cook until translucent, about 5 minutes.
Add garlic to mixture and cook, but do not burn, about 2 minutes.
Add red pepper flakes and basil, stir to combine.
Remove pan from heat and add vodka. Return to the heat and cook for about 1 minute.
Add marinara sauce and pancetta, simmer for 3 minutes.
Add cream and bring sauce to a boil. Boil for 5 minutes until sauce thickens, stir to prevent sticking.
Stir in 3/4 a cup of parmesan cheese into sauce.
Stir pasta into sauce and serve. Top with grated cheese.
