1. In a bowl, mix together the milk, sugar, eggs, and yeast. Add the flour, butter, and salt, then mix well. Let it rise for about 1 hour.
2. Lightly flour the work surface, shape the dough into a ball, then divide it into 16 equal pieces. Take the first piece, place half a slice of raclette cheese on top, then fold the dough to form a ball. Wrap each ball in plastic wrap and let it rest for 45 minutes.
3. Preheat the waffle iron, lightly grease it, and place one ball in each mold. Close it and let it cook.