My OHs mum wouldn't let any of her sons leave the house until they could make this traditional Welsh dish which I think is called something like Tatis Piminute. It's very easy, filling and sustaining...

Slice up an onion and fry it until soft. Add chopped bacon and fry that until cooked. Add potatoes, sliced into quite fine rounds, and enough water or stock to cover. Simmer it all with a good pinch of salt and pepper until the potatoes are soft and starting to fall apart - enjoy in large bowlfuls with crusty bread.