Meanwhile, in a medium skillet, cook the pancetta over medium-low heat until the fat is rendered, about 7 minutes. Using a slotted spoon, transfer the pancetta to a small bowl. Pour the pancetta fat into the drained spaghettini and toss together with 1/2 cup cheese and 1 teaspoon pepper. Swirl a small forkful of spaghettini into each muffin cup until about one-third full.
In a medium bowl, beat the eggs. Stir in the heavy cream and season with salt. Add about 1 tablespoon egg mixture to each muffin cup. Sprinkle the remaining 1/4 cup cheese and the pancetta on top. Bake until lightly golden around the edges, about 20 minutes.