Preparation

• Shape the dough into a 9×13-inch rectangle that will fit into a well-buttered 9×13-inch baking pan. Press the dough into the pan (don’t worry about any folds—they’ll add to the cake’s character). Cover the pan and proof the dough until it looks puffy but hasn’t doubled in volume, about 1-1/2 hours.
• Cut the chilled butter into tiny chunks and scatter them evenly on the dough surface. Push the butter chunks down to the bottom of the dough with your fingertip, taking care not to poke all the way through to the pan. Spread the dough with the sour cream and then sprinkle it with the sugar and sliced almonds.
• Position an oven rack on the top spot and then heat the oven to 400°F. Cover and proof the shaped dough until it’s large, puffy, and remains indented when lightly pressed with your fingertip, about 1/2 hour. Bake until golden brown, 15 to 20 minutes, rotating the pan halfway through baking. Let cool on a rack.