- Make the Dough 
- Warm milk and combine with yeast and 1 tbsp sugar; let sit 5–10 mins until foamy. 
- Mix remaining sugar, eggs, and melted butter in a large bowl. 
- Stir in yeast mixture. 
- Gradually add flour and salt; knead until smooth and elastic (about 5 mins). 
- Place dough in oiled bowl, cover, and let rise in warm spot until doubled (60–90 mins). 
- Prepare the Filling 
- In a saucepan, cook blackberries, brown sugar, cornstarch, and lemon juice over medium heat. 
- Slightly mash berries and cook until thickened (5–7 mins). Let cool completely. 
- Assemble the Rolls 
- Punch down dough and roll into 16x12 inch rectangle. 
- Spread softened butter, then cooled filling. 
- Roll up tightly and cut into 12 even rolls. 
- Place in greased baking dish, cover, and rise again 30–45 mins. 
- Bake and Glaze 
- Preheat oven to 350°F. 
- Bake 25–30 mins until golden and hollow-sounding when tapped. 
- Mix glaze ingredients; drizzle over slightly cooled rolls.