Preparation Steps

• Bloom yeast: In a large bowl, whisk the warm milk and 0.25 cup granulated sugar. Sprinkle the yeast over the top, stir, and let sit until foamy, 5 to 10 minutes.
• Make dough: Whisk in the melted butter, eggs, and salt. Add 3.5 cups of flour and mix until a shaggy dough forms. Add the remaining 0.25 cup flour as needed until the dough is soft and slightly tacky but pulls away from the bowl.
• Knead: Turn the dough onto a lightly floured surface and knead until smooth and elastic, 8 to 10 minutes. Shape into a ball and place in a greased bowl, turning to coat.
• First rise: Cover and let rise in a warm spot until doubled in size, about 60 to 90 minutes.
• Prepare fillings: In a small bowl, mix brown sugar and cinnamon. In another bowl, toss blackberries with 0.5 cup granulated sugar, cornstarch, and lemon zest.
• Roll dough: Punch down the dough and roll it into a 12 by 18 inch rectangle on a lightly floured surface.
• Fill: Spread the softened butter over the dough. Sprinkle the cinnamon-brown sugar evenly, then scatter the blackberry mixture over the top.
• Roll and slice: Starting from a long side, roll into a tight log. Trim the ends if needed, then slice into 12 equal rolls.
• Second rise: Arrange rolls in a greased 9 by 13 inch baking pan. Cover and let rise until puffy, 30 to 45 minutes. Meanwhile, preheat oven to 350°F.
• Bake: Bake until golden on top and bubbling at the edges, 22 to 28 minutes. Let cool in the pan for 15 minutes.
• Glaze: Beat cream cheese, powdered sugar, vanilla, and milk until smooth and pourable, adding a splash more milk if needed.
• Finish: Drizzle glaze over warm rolls. Serve slightly warm.