Grease and line a 23 cm / 9 in round cake pan.
Mix flour, sugar, yeast, and salt in a bowl. Add warm milk, egg, vanilla, lemon zest, and butter. Knead 8 to 10 minutes until smooth and elastic.
Cover and let rise until doubled, about 60 to 75 minutes.
Spread the dough gently into the pan. Let rest 20 minutes.
For the topping, melt butter, sugar, honey, cream, and salt in a saucepan. Stir in almonds and cook 1 minute. Cool slightly.
Spoon the almond topping evenly over the dough.
Bake at 180°C / 350°F for 25 to 30 minutes until deep golden. Cool completely.
For the filling, heat the milk until steaming. Whisk yolks, sugar, cornstarch, and vanilla in a bowl. Gradually whisk in hot milk, then return to the pan.
Cook over medium heat, whisking, until thick and glossy. Stir in butter. Cover the surface and chill completely.
Fold whipped cream into the cold vanilla custard.
Slice the cake horizontally with a serrated knife. For easier cutting, mark the top first through the almond layer.
Spread the cream filling over the bottom layer, replace the top, chill 30 to 60 minutes, then slice and serve.
Dish type
German dessert cake