Begin by boiling a large pot of salted water over high heat. Once boiling, add the shell pasta and cook until al dente, about 8 minutes, stirring occasionally. Reserve 1 cup of the starchy pasta water, then drain the rest and set the pasta aside.

In a large skillet, heat over medium-high heat and add the pancetta. Sauté for about 5 minutes until crispy and golden brown. Remove the pancetta and let it drain on a paper towel.

In the same skillet with the pancetta drippings, add the tablespoon of butter and let it melt. Add the finely diced onion and sauté for about 3 minutes until soft. Add the chopped garlic and cook for an additional minute until fragrant.

Pour the heavy cream into the skillet and add the black pepper. Bring to a gentle simmer and cook for about 5 minutes until it thickens slightly.

Stir in the shredded Parmesan cheese until melted and smooth. Fold in the thawed peas and cooked pancetta. Gradually add reserved pasta water as needed for desired consistency. Toss the cooked pasta into the skillet.

Once combined and heated through, remove from heat. Serve immediately, garnished with fresh parsley and extra Parmesan cheese.