Bring a large salted pot of water to boil. Add the pasta nests and boil for 7-9 minutes until al dente.
While the pasta is cooking, add oil to a large pan over medium heat and saute the onions until translucent or about 4-5 minutes.
Add the garlic and saute for another minute until fragrant. Toss in the frozen peas and let them heat for a minute or two.
Add in the butter, cream, and parmesan and cook on medium-low until the sauce thickens. Add salt and pepper to taste.
When the pasta is done, drain and add to the sauce mixture along with the reserved pasta water if your sauce is too thick.
Remove from heat and serve warm. Top with additional parmesan and salt and pepper if desired.
Store leftovers in an airtight container in the fridge for 3-5 days.
