Warm the milk lukewarm. Crumble yeast into it and dissolve it. Put 200 g flour, 30 g sweetener, 20 g butter, egg, lemon zest and 1 pinch of salt in a bowl. Add yeast milk and knead everything into a smooth dough.
Leave in a covered warm place for at least 45 minutes.
Melt 40 g butter and let it cool down a little. Knead 60 g flour, 30 g sweetener, almonds, 1 pinch of salt and butter into crumbles. Chill for about 30 minutes.
Form the dough into a roll on some flour and cut it into 9 pieces. Form dough pieces into flat talers and place them on a baking tray lined with baking paper. Spread plums and crumble on top and press on a little.
Let the thalers go again for about 15 minutes. Bake in the hot oven (electric cooker: 200°C/circulating air: 175°C/gas: level 3) for about 20 minutes until golden brown.