Begin by cooking your pasta in boiling, salted water until shy of al dente. Right before you drain, reserve about a cup of pasta water and set aside.
While the pasta cooks, heat olive oil and butter in large skillet until butter is melted. Medium heat.
Add pancetta to skillet and cook until it starts to brown and get slightly crispy. About 5-6 minutes.
Add garlic to the pancetta and cook until fragrant. Be careful not to brown the garlic. About 2-3 minutes.
Add in peas (they can still be frozen) and heavy cream. Stir. Let the cream start to simmer and thicken. About 5-8 minutes.
To the sauce, stir in parmesan cheese. Add salt and pepper, to taste.
Reduce heat to low. Add pasta to sauce and stir to coat. As you stir, slowly add in some of your reserved pasta water. You may not need the entire cup. Let it all heat together until the pasta is creamy and nicely coated.
Garnish with extra parmesan and chopped parsley before serving.