For the vanilla pastry cream :

1. In a medium bowl, whisk together eggs, sugar, and vanilla extract.
2. Melt butter in a medium size saucepan, then add the egg mixture, and whisk vigorously. Pour in the milk and heat on low, stirring constantly, about 5-10 minutes.
3. Whisk in cornstarch and let simmer until mixture thickens, stirring often. Remove from heat and set aside.

For the dough:

1. In a medium size mixing bowl, mix together melted butter with lukewarm milk. Add instant yeast, baking powder, and whisk well. Set aside for about 10 minutes. Add in the eggs, stirring after each addition.
2. In a large mixing bowl, mix flour, sugar and salt. Add the dry ingredients to the wet ones, stirring until the dough comes together. The dough should be slightly sticky.
3. Knead the dough – either by hand or using a stand mixer – for about 10 minutes. Cover the bowl with cling film and let the dough rise in a warm place until doubled in size, about 1 o 2 hours.
4. Line a baking tray with parchment paper. Grease with butter and flour, and set aside.
5. Roll out the dough in a large rectangle, then spread the vanilla pastry cream evenly onto the whole surface. Sprinkle raisins over.*
6. Roll the dough on the longer side in a long snake, then cut in 15 equal parts. Transfer the rolls onto the baking sheet, cover with a cloth, and let rise for about 30 minutes.

For brushing:

1. Preheat the oven to 400°F (200°C).
2. In a small bowl, whisk the yolks with milk. Brush the rolls with this mixture,and bake for about 20 minutes, or until pains aux raisins are golden-brown.
3. Remove from the oven and transfer to a cooling rack. Once cooled, brush with apricot jam to give a great glaze to pains aux raisins.