Frittatas are quite forgiving, so if you have other items on hand by all means substitute them. I used Parmesan and ham because it’s what I had, but Swiss and bacon would be good, too. Remember that farm-fresh produce comes in odd shapes and sizes, so pay attention to that potato before you slice it. Mine were small, about the size of a lemon, so I used three but you might only need one. Same goes for onions (mine was a large yellow). Lastly, this recipe is easiest in a nonstick skillet, but many folks frown on them for health reasons; I’ll leave that up to you.
Frittata with Caramelized Onions, Ham and Potatoes
Slice an onion in half, then cut into thin slices and cook in a large ovenproof skillet in a tablespoon or two of olive oil over medium heat about 15 minutes, stirring occasionally, until onions are light brown and very fragrant. Add a few splashes of balsamic vinegar to deglaze the pan and further color the onions. Remove from pan, then add another 1-2 T of olive oil. When it’s hot, cut a large potato (or three small ones) into thin slices and add it to the pan, letting it cook on medium about 10 minutes. Add in some diced ham and continue cooking until the potatoes are tender, about 10 minutes more. Mix with the onions in a medium bowl and season with salt and pepper.
Preheat the oven to 350 degrees. Add a tablespoon or two of butter to the skillet. When it’s melted, add the onions, potatoes and ham back in. Whisk 8 eggs with 1/2 cup of Parmesan and pour it over the veggies. Reduce the heat to medium-low and let cook without stirring until the bottom is set, about 10 minutes. Put the skillet in the oven and bake about 10-15 minutes more, checking periodically until the eggs are firm on top.