For the preferment, dissolve the yeast in water. Gradually add the flour and mix well. Cover the bowl and leave to rest in the fridge overnight (up to 18 hours). Cover the raisins with water and allow them to rest overnight as well.

For the dough, the next day dissolve 20 g yeast in 150 g water. Then mix the preferment in it. Slowly add the remaining flour and knead everything into a homogeneous dough. Add the salt and butter and knead for another 20 minutes or until the dough comes away from the sides of the mixing bowl or the work surface. Drain the raisins from the water and pat dry.

Place the dough on a floured surface and flatten gently to form a large, flat square. Cover the surface of the dough evenly with the raisins. Now roll up the dough, first lengthwise, then widthwise. Leave to rest for 30 minutes. Repeat the process of stretching and rolling 2 more times. The dough rests for a total of 90 minutes.

Pre-heat the oven to 200°C (top and bottom heat). Divide the dough into 4 pieces and form baguette-like rolls. Bake these for about 30-40 minutes. The pani tramvai are ready when they are nice and crispy on the outside and the inside has reached a temperature of 96° C.