Wash squash and sliced. Put 1/3 cup vegetable oil in a large skillet. Put the squash slices in freezer bag and add flour, salt and pepper in freezer bag along with the squash slices and shake until coat well. Take the squash slices out of the freezer bag and put them in a hot skillet and put the onion in squash and cook on medium heat for 30 minutes until golden brown. Put on paper towels lined down on a platter.