Preheat the oven to 375 F.

Beat together the eggs with the salt and pepper (do not over-beat; just mix until the eggs mostly come together.) Stir in hot sauce if using and set aside.

In a large oven-proof non-stick skillet, melt butter over medium-high heat. Add the onions and cook for several minutes, stirring frequently, until the onions are soft and golden brown. Add peppers and cook for a couple of minutes. Add potatoes and cook for another few minutes.

Make sure all the ingredients are evenly distributed across the bottom of the skillet, then pour in the egg mixture so that it evenly coats everything. Let it sit on the burner for about one minute to set the edges, then put the skillet in the oven.

Watch the frittata as it cooks. Let it cook in the oven for 10-12 minutes until the eggs are set and slightly browned on top.

Slide the frittata out of the skillet and onto a cutting board. With a long serrated knife, slice it into wedges and serve warm. Garnish with a sprinkling of fresh thyme. Serve with fruit or a tossed salad.