Melt half of the butter and olive oil in skillet, when hot add alternate layers of potatoes and onions and seasonings. Sprinkle with crumbs. Cook slowly until well browned on bottom.
When nearly done turn out on a flat plate lined with a paper towel.
Add the rest of the butter and oil to the skillet and slide the potatoes back into the skillet, browned side up. Cook until browned on bottom.
(opt) Add cooked bacon to the potatoes before cooking. Or chopped bell pepper.