Grease a springform pan (Ø 26 cm) and line the base with baking paper. Preheat oven.
Top / bottom heat: approx. 180 ° C (preheated)
Hot air: about 160 ° C (preheated)
Gas: level 2-3 (preheated)
Batter:
Mix the soft margarine or butter in a mixing bowl with a hand mixer (whisk) until smooth. Gradually add the sugar and bourbon vanilla sugar while stirring until a thickened mass is formed. Stir in each egg for about ½ minute at the highest level. Mix flour with baking powder and cocoa, sift and stir in briefly on medium heat. Finally fold in the grated chocolate. Smooth out the dough in the mold. Peel the bananas, cut in half crosswise and turn in lemon juice. Place the bananas in a star shape on the dough. Put the tin on the wire rack in the lower third of the oven.
Baking time: about 40 minutes
Loosen and remove the springform rim from the cake and let the cake cool on the springform pan on a wire rack.
Remove the bottom from the baking paper and place on a cake plate. Strain the apricot jam through a sieve and bring to the boil in a small saucepan. Brush the surface of the cake with the jam using a pastry brush.