Preheat oven to 400°F (200°C). In a large saucepan, combine blueberries, 3/4 cup (175 mL) sugar, lemon zest, lemon juice, nutmeg and cinnamon. Bring to a boil, reduce heat and simmer 5 min. Place in an 8 cup (2 L) baking dish.
Meanwhile, in a bowl, combine flour, baking powder, remaining 1 tbsp (15 mL) sugar and salt. Cut in cold butter until mixture resembles coarse oatmeal. Stir in just enough milk, about 1 cup (250 mL), to make a soft dough.
Divide dough into 8 equal portions and place them, evenly spaced, on blueberry mixture. Bake until biscuits are firm and no longer doughy and blueberries have thickened slightly, 20 to 25 min.
To serve, place a biscuit in each serving dish. Spoon blueberries on top, and add a scoop of frozen yogourt on the side.