Bring a large pot of salted water to a boil. Add the tortellini and cook according to package instructions until al dente. Reserve 1/4 cup of pasta water before draining.

In a medium bowl, whisk together the eggs and grated parmesan cheese until smooth and well-combined. Set aside.

In a large skillet, cook the diced pancetta or bacon over medium heat until crispy, about 5-7 minutes. Add the garlic during the last minute of cooking for additional flavor, if desired. Remove the skillet from the heat.

Add the drained tortellini to the skillet with the pancetta. Pour the egg and cheese mixture over the pasta, stirring constantly to prevent the eggs from curdling. The residual heat will create a creamy sauce. Add reserved pasta water, a tablespoon at a time, until the sauce reaches your desired consistency.

Season with freshly ground black pepper to taste, and add salt if needed. Garnish with extra parmesan and fresh parsley if desired. Serve immediately and enjoy!