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.
Press the dough by hand into a rectangle (approx. 20 x 30 cm) 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 over to the end.
Press the dough slightly flat at the bend to create the typical stollen shape.
Bake on a baking tray lined with baking paper in a preheated oven (electric cooker: 175 °C/ circulating air: 150 °C/ gas: see manufacturer) for approx. 1 1/2 hours. After 1 hour 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.