Zopf, which translates to 'braid' or 'pigtail', is a symbol of Swiss culinary tradition. It is a rich, leavened bread that is braided from 2, 4, or 6 strands (most commonly two). It is less sweet than similar European braided breads and its tenderness is guaranteed by the use of butter and milk instead of water. It is ideal served with jam and butter.
Dissolve the yeast and sugar in lukewarm milk. Let stand for 10 minutes until a foam forms (starter).
In a large bowl, mix the flour and salt. Add the starter, softened butter, and egg.
Knead into a smooth and elastic dough. Kneading should take about 10-15 minutes (by hand or with a mixer).
Form the dough into a ball, place it in a lightly greased bowl, cover with a cloth, and let rise in a warm place for 1.5 to 2 hours until the dough doubles in volume.
Turn the risen dough onto a lightly floured surface and divide it into two equal parts.
Roll each part into a long strand, with one end slightly thicker.
Lay the strands across each other and braid them into a simple plait (like braiding hair with two strands). Press the ends firmly under the loaf.
Transfer the braided loaf to a baking sheet lined with parchment paper. Cover and let it rise again for about 30 minutes.
Preheat the oven to 185 °C (365 °F).
Brush the Zopf with the beaten egg and bake in the preheated oven for 25-35 minutes until golden brown and cooked through. If the loaf browns too quickly, you can cover it with aluminum foil.