"Frittata." It's a great word, a Nabokovian word. The kind of word I imagine Giada de Laurentiis over-enunciating in a tight t-shirt to a soft-lens camera.
Free. Ta. Ta.
And it's every bit as delicious to eat as it is to say.
In the meantime, thinly slice about one pound of potatoes and 1 onion. Again, use the mandoline if you have one, as the uniform slices of potatoes and squash will make for more even cooking and elegant presentation.
Heat 2 tbsp. of olive oil or butter in a large oven-proof, non-stick skillet. Saute the potatoes and onion over medium-low heat, stirring and flipping often, until the potatoes become soft. If you cover the pan with a lid and slice the potatoes thinly, the process should take about 15 minutes. Once potatoes are soft, raise the heat to medium high and allow potatoes to become brown and crisp. Remove potatoes with tongs or a slotted spoon but keep the pan on the stovetop.
Pat dry the squash with paper towels or a kitchen towel. Add the squash to the pan and saute for about 4 minutes, until the squash is tender and develops a little color. Then remove the squash with tongs or a slotted spoon.