Serve the frittata alongside arugula tossed with lemon vinaigrette and wedges of ciabatta.
Heat the oven to 375°F. In a large bowl, whisk together the eggs, 1/2 teaspoon salt, 8 grinds pepper, and the red pepper flakes until smooth. Set aside. Heat 2 tablespoons oil in a heavy, nonstick, oven-proof frying pan over medium heat.
When the oil is hot, add the garlic and sauté until aromatic, about 1 minute. Immediately add the remaining oil and the broccoli (you don't want the garlic to burn). Sprinkle the broccoli evenly with 1/4 teaspoon salt and 8 grinds pepper, and sauté until tender but still slightly firm, about 5 minutes (poke with a fork to check).
Make sure the broccoli florets are evenly spaced in one layer, and then pour in the seasoned egg mixture. Gently shake the pan so the eggs spread evenly. Arrange the peppers and cheeses evenly over the top of the frittata, and let it continue to cook until the edges are set, about another 4 minutes.
Transfer to the oven, and cook until the eggs are firm and the cheese has melted, about 15 minutes. Let cool slightly, then serve straight from the pan or on a platter pepper side up.