1. Peel the small potatoes and steam them for 15 minutes.
2. Preheat the oven to 350°F.
3. Immerse the skate wings in a pot of boiling salted water with the addition of white vinegar. Cook for 10 minutes as soon as the water boils.
4. Drain the skate. Remove the cartilage and skin (it’s best to do this while it’s hot, otherwise the flesh sticks to the cartilage). Arrange the flesh in an oven-safe dish.
5. Remove the crust from the bread slices and cut the crumb into small cubes.
6. In a pan, melt the butter. Add the bread cubes. When they start to brown, add the lemon juice and capers. Stir for 1 minute, pour the contents of the pan over the skate, and put the dish in the oven for 5 minutes.
7. Remove from the oven and serve immediately with the potatoes.