Pain aux Raisins Swirl Bread

Prepare the Dough

1. In a large bowl, combine bread flour, yeast, granulated sugar, and salt. Mix well.
2. Add lukewarm milk and egg to the dry ingredients. Mix until a shaggy dough forms, then knead for 5 minutes.
3. Gradually add the softened butter, kneading until fully incorporated and the dough is smooth and elastic, about 10-12 minutes.
4. Place the dough in a lightly oiled bowl, cover, and let rise in a warm place for 1-1.5 hours, or until doubled in size.

Assemble the Swirl Bread

1. Once doubled, gently punch down the dough and turn it out onto a lightly floured surface.
2. Roll the dough into a large rectangle, approximately 12x18 inches (30x45 cm).
3. Evenly spread the cooled custard over the entire surface of the rolled dough, leaving a small border free on one long edge.
4. Sprinkle the raisins over the custard.
5. Starting from the long edge opposite the bare border, tightly roll the dough into a log.
6. Pinch the seam to seal. Gently transfer the log to a parchment-lined baking sheet.

Bake the Bread

1. Cover the log loosely with plastic wrap and let it rise for another 30-45 minutes, or until puffed.
2. Preheat oven to 375°F (190°C).
3. In a small bowl, whisk together the egg yolk and milk for the egg wash. Gently brush this mixture over the risen dough.
4. Bake for 25-30 minutes, or until golden brown and cooked through. If browning too quickly, loosely tent with foil.
5. Remove from oven and let cool on a wire rack before slicing and serving.