Frittata with pancetta

8 ounces pancetta , diced 6 ounces shallots , peeled and thinly sliced 12 eggs 1/4 teaspoon kosher salt fresh ground black pepper 4 ounces gruyere cheese ,[...]

1 tablespoon olive oil 1/8 lb pancetta or 1/8 lb other tasty bacon 2 garlic cloves , crushed 1 bunch greens , like swiss chard, ribs removed and leaves[...]