In a large bowl, crumble the yeast into the cold milk, then add the egg and the rest of the dry ingredients (except the ingredients for the filling). Knead the batter in a mixer with a dough hook. Add the flour little by little as the machine kneads the dough. Then add the room-temperature butter. Turn the mixer off and let the dough rise in a place with no drafts for around 2 hours. Cover the bowl with a cloth.

Preheat the oven to 375°F. Turn out the dough. With a rolling pin, roll the dough into a long plank around 4 inches thick. Sprinkle the filling ingredients over the dough: the butter pieces, the dark chocolate, and the pistachios. Then roll up the dough into a log. Cut 12 equal-sized rolls out of the log. Butter a 10-inch springform pan and place the rolls into the pan, so they are not packed too tight. Then let them rise for another 30–45 minutes. They’ll fill out the pan as they rise. Bake the rolls on the bottom rack for around 30 minutes. If the tops of the rolls are getting too dark, cover the pan lightly with foil. When cooked, let the Boston rolls cool slightly and then remove the entire cake from the pan. Cut into pieces. Sift confectioners' sugar over the tops.

Photography by Food+styling by Sanna Kekalainen | Photography by Reetta Pasanen