Cook the potatoes in salted water for approx. 20 mins. until very soft. Drain the water and allow the residual moisture on the potatoes to evaporate in the pan. Push the potatoes through a sieve or mash them with a potato masher. Stir in the milk and butter. Mix the flour with the baking powder, add to the potato mixture, season and combine thoroughly to form a smooth batter. Heat the waffle iron and brush with a little clarified butter. Spoon 2 heaped tablespoons of the batter per waffle onto the iron, bake the waffles for approx. 4 mins. each, remove and serve at once or keep warm in the oven.
Heat the oil in a pan. Add the peas, pour in the stock and simmer for a few minutes until the peas are soft and the stock has been absorbed. Allow to cool slightly. Place the peas in a blender with the mint leaves and finely puree. Add the lemon zest and juice, season.
Serve and garnish
Serve the mousse with the waffles, garnished with peas, sprouts and mint.