In a small bowl, put half of the warm milk, add the yeast and half the sugar, mix, and let rest for 5 minutes.
In a large bowl, put the flour and the salt.
Add the rest of the warm milk, the eggs, and the activated yeast mixture.
Mix until combined.
Add the butter, cut into small chunks, and knead until the dough is smooth and elastic.
Cover the dough with a towel and let it rise for 1 hour in a warm place.
Roll out the dough into a rectangle. Brush with melted butter and spread the mustard.
Add the ham and the cheese evenly across the surface. Roll tightly into a log.
Cut into slices about 3 centimeters thick and arrange on a parchment-lined baking tray. Let it rise for another 30 minutes.
Brush with egg wash or a little milk.
Optionally, sprinkle a pinch of sugar on top.
Bake in a preheated oven at 180°C (350°F) for 15–20 minutes until golden brown.
Let cool slightly before serving.