Ingredients

• 1/2 cup (scant) milk, warmed to lukewarm
• 1 teaspoon active dry yeast
• 1 tablespoon granulated sugar
• 1 large egg
• 2 tablespoons butter, melted
• 1/2 teaspoon salt
• 1/2 teaspoon ground cardamom
• 1 1/4 cups all-purpose flour
• 3/4 cup sweet quark (or well-drained ricotta)
• 1 cup rhubarb, finely chopped
• a pinch granulated sugar, for the filling
• a pinch ground cinnamon
• for serving confectioners' sugar, for dusting

Equipment

• Large mixing bowl
• Rolling pin
• Springform pan
• Pastry brush
• Sharp knife

Instructions

1. Let all your ingredients come to room temperature first, which helps the yeast work and the dough come together smoothly.
2. In a large bowl, stir the yeast and 1 tablespoon sugar into the lukewarm milk (warm but not hot, about body temperature) and let it sit for a few minutes until it looks foamy, a sign the yeast is alive.
3. Mix the salt into the flour, then stir about half of it into the yeast mixture and beat briefly until you have a loose batter.
4. Sprinkle a little flour on top, cover the bowl with a towel, and set it in a warm spot to rise for about 1 hour, until bubbly and puffed.
5. Beat the egg and set aside about 1 teaspoon for brushing later. Add the cardamom, the melted butter, the rest of the beaten egg, and the remaining flour to the risen batter.
6. Knead the dough well, right in the bowl or on the counter, until it turns smooth and pulls cleanly away from the sides, about 5 to 8 minutes.
7. Cover again and let it rise in a warm place for about 1 hour, until doubled in size.
8. Roll the dough into a square. Spoon the quark into the center, fold the edges over to enclose it, then gently roll out again into a rectangle so the quark spreads through the dough.
9. Scatter the rhubarb, a pinch of sugar, and a pinch of cinnamon over the rectangle, leaving about a 1-inch border bare along one long edge so the roll seals.
10. Roll it up snugly toward the clean edge, then slice into 6 or 7 equal rolls. Tuck the loose end of each under to form a flat bottom.
11. Butter a springform pan and arrange the rolls cut side up like a flower: one in the center and the rest around it, leaving a little space to rise.
12. Cover and let rise 20 to 30 minutes, then brush the tops with the reserved beaten egg for a glossy finish.
13. Bake at 350 degrees F for 20 to 30 minutes, until golden and cooked through. Cool slightly, then dust with confectioners' sugar before serving.