Leftover Focaccia

We recently ate Dutch potato-vegetable mash on a day when the weather was gloomy—I was actually looking for an excuse to eat smoked sausage, so I chose a dish to go with it. We had just a bit left; not quite enough for the day after, and it would be a shame to simply throw it out. Suddenly I remembered my own old recipe for potato focaccia made with mashed potatoes; potatoes are the bomb when used in bread. They make it soft and spongy, and it becomes a comforting kind of bread that you’d w