Place a large pot over high, season with salt and cook pasta to al dente. Drain well, saving ½ cup of pasta water.
While the pasta is cooking, place a large skillet over medium heat, add butter, sliced onions and red pepper flakes. Saute for 4-5 minutes until the onions soften. Add the vodka sauce and warm through.
Next add the raw shrimp directly to the sauce. Simmer 3–5 minutes until pink and cooked through, remove from heat.
Toss in pasta and stir to coat. Be sure to mix it together well. Add the heavy whipping cream and about ¼ cup pasta water. Again toss and coat the pasta. You want the pasta plenty saucy!
Top with Parmesan and minced parsley. Serve and enjoy!
Notes
*I got a great price and used extra large shrimp for this recipe. I recommend it for this recipe, but of course use what you can afford.