Peel the ginger and chop about 30 g coarsely. Mix baking mix, fat, egg, 1/8 litre water and ginger to a smooth dough. Divide a rectangle (approx. 18x32 cm) on a greased baking tray with aluminium foil folded several times.
Spread the dough on it. Bake in the preheated oven (electric oven: 200°C/ gas: level 3) for approx. 20 minutes. Let it cool down. Drain ginger plums, cut into thin slices and halve.
Finely chop the remaining fresh ginger or press it through a garlic press. Mix icing sugar, ginger, lemon juice and 1-2 teaspoons of ginger syrup to a smooth glaze. Spread on the gingerbread and cover with ginger plum slices at regular intervals.
Allow to dry and cut into about 18 squares.