Preheat the oven to 350F.
Melt the butter in a small pan over low heat, and let it cool.
Combine milk with yeast. Cover and let it stand for 10 minutes.
Add egg and sugar to a large mixing bowl. Whisk until the mixture becomes light and creamy.
Add in melted butter and whisk again to combine.
Stir in the yeast and add the sifted flour, combine with a pinch of salt.
Knead until you get a homogeneous and smooth dough.
Place the dough into a large, clean bowl, and cover it with a kitchen towel. Let it rise in a warm place until it is doubled in volume.
Place the dough on a lightly floured surface and knead it for a minute.
Place the dough in small paper panettone molds and let it rise again until it has doubled in volume.
Gently brush the surface of the dough with the beaten egg and sprinkle with pearl sugar.
Bake for 40 to 45 minutes.
Let it cool completely and serve.
Enjoy.