Position a rack in the upper third of the oven; preheat to 425°.
Bring a large pot of water to a boil for the pasta. Salt the water, add the pasta and cook until a few minutes shy of al dente, about 6 minutes; drain.
In an ovenproof skillet, heat the oil, three turns of the pan, over medium-high. Add the pancetta and cook, stirring often, until beginning to brown, about 2 minutes. Add the garlic and pepper and stir until aromatic, about a minute. Mix in the pasta; season with salt. In a large bowl, whisk the eggs, cheeses and milk. Pour over the pasta, shaking the pan to settle the eggs into the pasta. Bake until puffed and cooked through, about 15 minutes.
Serve the frittata hot or at room temperature, topped with small handfuls of the herbs and greens.