Combine the finger-sized pieces of squash, onion and a little salt, to taste in a large mixing bowl. Add flour in two-tablespoon increments, tossing the mixture continuously with a large mixing spoon or your hands, until it is a little gummy from the flour.

In a large, deep frying pan, heat about ¼ inch of olive oil and take 3 1/2 cups of the filling and empty it into the frying pan, flattening out with the back of a spoon so that it looks like a large, thick pancake. Fry over medium heat until the bottoms are brown and crusty.

Remove from heat and place a large plate or the frying pan lid on top, making sure that either covers the entire surface and then some. Using pot holders, very carefully flip the hot frying pan over so that the cooked side of the skillet pie is on top. Slide that back into the pan to continue cooking on the other side, until golden. Slip onto a platter, replenish the olive oil as necessary and continue making more skillet pies in the same way, until the squash mixture is used up.