Wash the lemon and grate dry. Grate lemon peel. Mix sultanas, currants, candied lemon peel, candied orange peel, lemon peel and rum. Leave to stand for at least 1 hour.
Knead flour, baking powder, sugar, salt, eggs, 125 g butter, lard, curd and stollen spices first with the dough hooks of the hand mixer, then with your hands to a smooth dough. Knead in soaked fruits, hazelnuts and almonds.
Cut the dough in thirds. Press each third into a rectangle (approx. 15 x 18 cm) by hand on a floured work surface. Make a groove in the outer third of a long side by hand.
From the opposite long side, do not fold the dough completely to the end. Press the dough a little flat at the bend to create the typical stollen shape.
Place the stollen side by side on a baking tray lined with baking paper and bake in a preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 50 minutes. After 35 minutes baking time cover the stollen with aluminium foil and place another baking tray underneath.
Melt 75 g butter in a small pot. Take out the stollen, brush with liquid butter while still hot and dust with icing sugar. Let the stollen cool down.