Cover the raisins (barely) with warm water and let sit.
Combine the egg, yolks, sugar, buttermilk, and melted butter in the bowl of a stand mixer and beat with the whisk attachment until combined. Add about half of the flour, the salt, yeast, and continue to beat at low speed until the mixture resembles cake batter. Drain the raisins and add to the batter. Add all but about 1/2 c. of the remaining flour, switch to the dough hook, and knead for 5 minutes. After 5 minutes, check the consistency of the dough; it should be smooth, and pulling away from the sides of the bowl. If it's sticky, add enough flour to get the desired texture. Continue to knead for 5 minutes more, then turn out onto a floured surface, form into a ball, and place into a large bowl that's been oiled lightly. Lightly oil the top of the dough as well, cover loosely with plastic wrap, and allow to rise until doubled, 2 to 2 1/2 hours.
After the dough has risen, butter the interior of a 9"x13" glass baking dish well. Turn out the dough onto a floured surface, punch it down, and roll it out into a 12"x18" rectangle. Brush on melted butter, leaving the outer 1" of one of the 18" edges clear. Combine the brown sugar and cinnamon, and sprinkle it into an even layer over the buttered area of the dough, then press it in lightly with your hands. Starting on the other 18" side (the one with the filling), roll up towards the clean 18" edge, forming a tight cylinder. Pinch the edge to seal, then cut into 12 equal sections with a serrated knife. Arrange in 4 rows of 3 in the glass dish, then wrap tightly with plastic wrap and put in the refrigerator overnight.
In the morning, when you're ready to bake, remove the plastic wrap and place the rolls into a cold oven. Place a baking dish on the shelf below the rolls, and fill it about 2/3rds with boiling water. Close the oven door and let sit for about 30 minutes. The dough should puff up a bit. Remove the rolls and the water from the oven, and preheat the oven to 350°F. Bake until golden brown, and the interior reaches 190°F, about 30 minutes. Remove from the oven and let cool slightly while you make the frosting.
To make the frosting, beat the cream cheese until smooth, then beat in the milk. Add the confectioners sugar and beat until the whole mass comes together. Frost the rolls and serve.
This recipe calls for the dough to rest overnight, so plan ahead!