Blackberry-Hazelnut Sticky Buns - unsalted butter

Method

• For the topping: Grease a 12-cup standard muffin tin with butter, even if using a nonstick tin.
• Combine the blackberries, granulated sugar and lemon juice in a small bowl.
• Let this macerate at room temperature for 30 minutes.
• Mash with a fork, then strain the juice into a small bowl and discard the solids.
• Melt the butter in a small saucepan over medium heat.
• Whisk in the muscovado sugar and blackberry juice and cook until the mixture is smooth and slightly thickened.
• Divide the caramel mixture among the cups then divide the hazelnuts over the caramel.
• For the filling: Preheat the oven to 375 degrees F. Place the tin on a sheet pan lined with parchment paper.
• Lightly flour a flat surface.
• Unfold each sheet of puff pastry onto the floured surface and lightly roll out with a rolling pin to an even thickness.
• Brush both sheets with the butter leaving a 1-inch border on the puff pastry.
• Divide the blackberries over the butter.
• Combine the granulated sugar and cinnamon in a small bowl and sprinkle over the surface of each sheet.
• Starting with the end nearest you, roll the pastry up snugly like a jelly roll around the filling, finishing the roll with the seam-side down.
• Trim the ends of the roll about 1/2 inch and discard.
• Slice the roll in 6 equal pieces, each about 1 1/2-inches wide.
• Place each piece, spiral-side up, in 6 of the muffin cups.
• Repeat with the remaining pastry sheet.
• Bake until the sticky buns are golden to dark brown on top and firm to the touch, 30 minutes.
• Remove from the oven onto a baking rack and let cool for 5 minutes.
• Use a small offset spatula to remove the buns from the tins, and place upside down on a serving platter.