For baked mice with must foam first melt the butter and let it cool a little. Finely grate the zest of half a lemon. Heat the milk until it is lukewarm.
Mix the butter, lemon zest, yolks, yeast, vanilla sugar, salt, pear juice and flour well and then add the milk. Knead into a smooth dough and let rest for at least 60 minutes.
Heat enough fat (do a cooking spoon test) and add the dough by tablespoons. When the mice are nice and crispy on the outside, drain briefly on paper towels.
Shortly before serving, whip all ingredients for the must foam over a water bath. Sprinkle the mice with powdered sugar. Serve the baked mice with must foam immediately.