Pour the cream into a mixing bowl, rinse the mug and dry it. Measure out the sugar and add to the cream with the vanilla sugar, as well as the 4 eggs, salt and Zirtroback. Mix well, then stir in the flour and baking powder. Place the batter on a baking sheet (either lined with parchment paper or a little greased). Bake in the preheated oven with top and bottom heat at 200 ° C on the middle shelf for 10 minutes.
In the meantime, prepare the glaze, mix the softened butter with the sugar, vanilla sugar and milk, add the almonds.
After the 10 min cake take out of the oven, spread the topping over the cake in the second rack from the top and bake for another 10 min.