Preheat oven to 190c and line a baking tray with grease proof paper.
In a large bowl add flour, dark brown sugar, baking powder and sea salt.
Add cold butter to the flour mixture and using a pastry blender mix into the flour until the flour is crumbly with little pieces of butter still present in the dough.
Add the roasted berries (try not to get too much of the juice into the mixture) to the flour mixture and lightly toss the berries in the mixture.
In a small bowl whisk together eggs, Greek yogurt, lemon zest and vanilla bean paste.
Add the liquid mixture into the flour mixture and carefully mix together, trying to not smash the berries too much. The mixture will be somewhat wet.
Flour a large cutting board or your counter and turn out dough. Flour your hands and form the dough into a 6 inch disk and about 3/4 inch thick. Cut into 8 pieces and place onto prepared baking sheet. If the dough is too soft let it firm up in the freezer for about 15 minutes before baking.
Brush the tops with milk and sprinkle with sanding sugar.
Bake for about 25 minutes or until fully cooked.