Adapted from Six Seasons by Joshua McFadden
Put the potatoes in a large pan of water and add salt until it tastes like the sea. Bring to boil and cook until they are tender but not mushy, 15-20 minutes, depending on their size. Drain. When cool enough to handle, cut into small chunks. Heat the oven to 400F.
Heat the butter in a 10-inch skillet (nonstick if you have one, with and ovenproof handle) over medium-high heat. Add the bell peppers and prosciutto, season lightly with salt and black pepper, and cook until fragrant and the bell peppers are softening but not browning, 5-7 minutes. Add the potatoes.
Crack the eggs into a large bowl, add 1 tsp salt, many twists of black pepper, and the parmesan. Whisk until the eggs are nicely blended. Pour the eggs over the ingredients in the skillet, scraping everything out of the bowl with a rubber spatula.
Reduce the heat to medium and let the eggs sit peacefully for about 2 minutes. Then carefully slip the spatula around the edges of the eggs, releasing them from the pan, allowing more liquid egg to flow underneath. Let that new layer of egg set up a bit and then repeat the process. You are building layers of cooked egg, which will help the frittata have a lighter texture.
After most of the liquid egg has cooked, but the top is still runny, a dollop the ricotta over the top of the frittata in 8 blobs, evenly spaced so each slice will get some ricotta. Transfer the pan to the oven and finish cooking the frittata all the way through, about 5 minutes. It should puff a bit and the op will get lightly browned.
Let the frittata sit in the pan for a couple minutes, then run the spatula around the edge and as far under the center as you can. Slide the frittata onto a cutting board or cooling rack. If a bit sticks to the pan and rips, don’t worry, just piece it back together.
Serve the frittata on the warm side of room temperature, cut into wedges. Top with cherry tomatoes. It’s delicious the next day too.