• Line a rimmed baking sheet with foil or parchment paper. Lightly grease an 8 or 9-inch baking pan, or oven-proof deep skillet and place on the prepared baking sheet. Set aside. Preheat oven to 375°F.

To prepare the blueberry mixture:

• In a large saucepan combine ¾ cup sugar, cornstarch and boiling water. Warm over medium heat until the mixture boils. Cook for 1 minute or until thickened. Add the blueberries and stir to combine. Gently cook the blueberry mixture for 1 minute then remove from the heat. Add the lemon zest and lemon juice.
• Pour the blueberries into the prepared pan. Cut the butter into small pieces and scatter on top of the blueberries. Set aside.

To prepare the biscuits:

• In a medium mixing bowl combine the flour, sugar, baking powder, baking soda and salt. In a small bowl whisk together the melted butter and buttermilk. Add the buttermilk mixture to the flour and sugar. Using a rubber spatula, stir until combined.
• Lightly coat a ¼ cup dry measuring cup with vegetable cooking spray. Scoop the biscuit dough into the cup (heaping) and dollop on top of the blueberries. You should have 9-biscuits spaced equally over the blueberries.
• Sprinkle coarse sugar over the biscuits. Bake for 30 to 40 minutes or until the biscuits are lightly browned and the berries are bubbling. Cool slightly before serving.