Broccoli Frittata

Name: Broccoli Frittata
Ingredients: 3 tablespoons unsalted butter; 2 shallots, sliced; 2 garlic cloves, thinly sliced; Kosher salt; Freshly ground black pepper; 3/4 pound broccoli, thick stems peeled, cut into flowerets; 1/2 cup water; 6 large eggs; 1/2 cup half-and-half; 1/4 cup finely grated Pecorino Romano cheese