Ingredients:
1-1/2 cups (225 grams) raisins
water to cover
3-1/2 tsp active dry yeast
1/2 cup plus 2 tablespoons warm milk (not hot)
1/2 cup (70 grams) unbleached all-purpose flour
3-1/4 cups (430 grams) unbleached all-purpose flour
1/2 cup (100 grams) sugar
1 tsp (5 grams) salt
2 eggs
1 egg yolk
grated zest of 1/4 lemon
grated zest of 1/4 orange
1/4 tsp vanilla extract
1 stick (115 grams) unsalted butter, room temperature
1/4 cup unbleached all-purpose flour for the raisins

Method:
Soak the raisins in cool water to cover at least 30 minutes; drain but reserve 
1/4 cup of the water. Stir the yeast into the warm milk in a small bowl; let 
stand until creamy, about 10 minutes. Add the flour and reserved raisin water 
and stir until smooth. Cover with plastic wrap and let rise until doubled, 20 to 
30 minutes. 

Place the flour, sugar, salt, sponge, eggs, egg yolk, grated lemon & orange 
zests, and vanilla in a mixer bowl and mix with the paddle until blended. Add 
the butter and mix thoroughly. Change to dough hook and knead at medium speed 
until soft, springy, and smooth except for a few blisters, 3 to 4 minutes. (Or 
by hand, knead until soft, springy, and very smooth, 8 to 10 minutes).

Place the dough in a buttered bowl, cover with plastic wrap, and let rise until 
doubled, about 1 hour.

Pat the raisins dry and toss with 1/4 cup flour. Add the raisins to the dough in 
1 or 2 additions by flattening the dough, patting the raisins over the surface, 
and rolling up the dough. Cut the dough into 16 to 18 pieces and roll each piece 
into a ball. Place the rolls on lightly buttered or parchment-lined baking sheets.
Cover with a towel and let rise half their original volume, about 45 minutes.

Heat oven to 400°F. Bake 18 minutes. The rolls should double in size and puff 
up into fat buns as they bake. Cool on racks.