01 -
Preheat oven to 200°C. Lightly grease a 23 x 33 cm baking dish with nonstick cooking spray.
02 -
In a large bowl, mix together flour, brown sugar, baking powder, baking soda, salt, and ground cinnamon with a fork until well combined.
03 -
Grate the frozen butter directly into the dry ingredients. Use a fork to gently toss until butter is evenly distributed and coated.
04 -
Pour in one third of the buttermilk and mix lightly with a fork. Gradually add the remaining buttermilk in two more additions, mixing just until dough is very soft and still wet.
05 -
Turn dough onto a floured surface. Dust the top with extra flour. Fold the dough in half twice, using more flour as needed to prevent sticking. Pat gently into a rectangle about 3 cm thick. Avoid kneading or rolling.
06 -
Scatter one third of the blackberries over the dough. Fold dough in half so berries are covered, patting lightly to reform a 3 cm thick rectangle. Repeat folding and incorporating berries in alternating directions until all blackberries are evenly distributed, sprinkling with extra flour as necessary.
07 -
Turn dough over gently. Pat sides to seal. Ensure dough is 2.5–3 cm thick. Cut out biscuits using a 6–7 cm biscuit cutter. Re-shape scrap dough and continue cutting until all dough is used.
08 -
Place biscuits close together in the prepared baking dish, with edge biscuits touching the sides. Bake for 20–25 minutes, or until tops and sides are golden brown.
09 -
While biscuits bake, whisk together melted butter, confectioners' sugar, lemon zest, and lemon juice in a small bowl until smooth.
10 -
Brush tops of hot biscuits generously with lemon glaze. Serve warm.