Cook fusilli in a pot of salted boiling water until al dente. Reserve a cup of pasta water.
In a skillet, fry pancetta in olive oil over medium heat until golden, about 5-6 minutes.
Add garlic and sauté for 30 seconds, ensuring it doesn't burn.
Toss in frozen peas and stir for another 30 seconds.
Pour in cream and bring to a gentle simmer. Adjust heat to avoid boiling.
Stir in black pepper and lemon juice.
Gradually add parmesan, allowing it to melt between additions.
Mix in the cooked pasta and ¼ cup reserved pasta water. Simmer for 1-2 minutes to thicken.
Season with salt and pepper. Add more pasta water if necessary.
Fold in half the arugula, then serve with remaining arugula and extra parmesan sprinkled on top.