Mix stock, vinegar and season to taste with sugar and pepper. Peel and wash the potatoes, cut into thin slices and dab dry. Mix the potatoes with 1 teaspoon of oil, place on a baking tray with baking paper and bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 20 minutes until golden brown
Clean, wash and shake spinach dry. Wash and halve the tomatoes. Grease a small coated pan with 1/2 teaspoon of oil, break the egg and carefully slide into the pan. Fry over medium heat until you have a fried egg.
Season with salt and pepper. Remove potatoes from the oven and salt them. Arrange the spinach, tomatoes and vinaigrette on a plate. Add the potatoes