Preheat the oven to 375 degrees Fahrenheit.

To make the filling: Rinse and drain the blueberries, then pick through them to remove any stems still attached. In a 9-inch square baking dish, combine the blueberries, maple syrup, starch, lemon juice and cinnamon. Stir until all of the powdered ingredients have disappeared into the mixture. Bake the filling for about 25 minutes, until the mixture is bubbling around all four edges.

Meanwhile, prepare the topping: In a mixing bowl, combine the flour, baking powder and salt. Whisk gently until combined, and set it aside.

In a small bowl, combine the sugar and lemon zest. Use your fingers to rub the zest into the sugar (this extracts more flavor from the lemon). Then, pour the sugar into the other dry ingredients and whisk to combine.

In the smaller bowl, combine the melted butter, yogurt and egg, and whisk until evenly combined. Pour the wet mixture into the dry mixture, and stir until well combined. It will look crumbly at first, but stir well until it forms a cohesive dough.

Dollop one large spoonful at a time over the hot filling, using the back of another spoon or your finger to help transfer each dollop. Sprinkle the sugar evenly over the dough.

Bake for 16 to 20 minutes, until the filling is actively bubbling around the edges and the top is lightly golden. Let the cobbler rest for 5 to 10 minutes before serving. Serve with vanilla ice cream, if desired.