Hazelnut and Apple Cake
Rinse potatoes thoroughly and cook for about 20-25 minutes in salted boiling water. Drain, peel and press through a potato ricer. Allow to cool slightly.
Mix butter with sugar and eggs well with the whisk of a hand mixer. Stir in yogurt and potatoes. Mix flour with milk powder and baking powder and mix into the batter with the hazelnuts.
Line the bottom of a springform pan of 24 cm (approximately 9 1/2 inches) diameter with parchment paper. Pour in the batter. Cut apples in half, peel, remove cores and carve the curved side of the apples with the tines of a fork. Place apples cut side down in the batter and lightly press in. Bake in preheated oven at 200°C (gas mark 2-3, fan: 180°C) (approximately 400°F) for about 40-45 minutes.
In a small saucepan, melt apricot jam and 1 tablespoon water. Brush top of the cake with the glaze. Allow the cake to cool. Remove from the pan, dust with powdered sugar and serve.