Pour the flour into a bowl and make a depression in the middle. Crumble the yeast into it. Pour milk into the yeast and mix with some flour. Cover the pre-dough and let it rise in a warm place for about 15 minutes.
Melt the fat, let it cool down a little. Cream eggs, 50 g sugar and salt. Add liquid fat. Pour into the yeast pre-dough and mix everything to a smooth, almost liquid dough. Cover and leave to rise for another 30 minutes.
Grease 9 savarin cups (approx. 10 cm Ø). Fill half of each mould with dough and leave to rise for another 20 minutes. Bake in the preheated oven (electric cooker: 200 °C/ gas: level 3) for about 20 minutes.
Drop onto a cake rack and let it cool down. Mix orange juice, liqueur and 1 packet of vanilla sugar and sprinkle the babas with it. Mix quark, 1 packet of vanilla sugar, lime juice, sugar and lime zest.
Whip the cream and cream firmer until stiff and carefully fold into the quark mixture. Pour into a piping bag with star-shaped spout. Halve 4-5 Babas. Fill the halved babas with the cream. Place the lid on top.
Squirt tuffs into the centre. Decorate lime slices, lime zest, lemon balm and star fruit as desired.