Melt the butter & let it cool down.
Mix flour, dry yeast, vanilla sugar & salt.
Whisk milk, molten butter & egg w/ an eggwhip.
Knead together the flour mix & the liquid mess. Add the raisins & knead well to distribute the raisins.
Form a ball & let it rest in the oven for about 45 min (covered w/ a tea towel). Preheat the oven to 50° C for about 2-3 min beforehand.
Knead the dough & form a roll. Cut it into 6 pieces & form small balls. Put them onto a baking tray lined w/ baking parchment. Let it rest in the warm oven for about 20 min. (Repeat the preheating of teh oven to 50° C for about 2-3 min.)
Take the baking tray out of the oven & preheat the oven to 160° C fan.
Whisk egg yolk & milk & brush the mix all over the buns.
Bake the buns for about 15 min.