Preheat your oven to 375°F (190°C). Spray a 9-inch deep pie pan with baking spray and place it on a baking tray to catch any spills. If you don’t have a deep pie pan, you can substitute with an 8x8-inch baking dish.

In a medium saucepan over low heat, whisk together the cornstarch and sugar until smooth. Add the blueberries, water, and lemon juice, stirring constantly as the mixture heats. Continue cooking until the filling thickens and the blueberries begin to release their juices. Remove from heat and set aside while you prepare the crust.

In a large mixing bowl, combine the flour, sugar, baking powder, and salt. Stir to blend the dry ingredients evenly. Add the melted butter, water, and beaten egg, whisking until you have a thin batter that resembles pancake batter.

Pour the batter into the prepared pie pan, spreading it evenly. Carefully spoon the blueberry filling into the center of the batter. As it bakes, the crust will rise up around the filling to create that signature “crazy crust” effect.

Place the pan in the oven and bake for 30–40 minutes, or until the crust is golden brown and the filling is bubbling. Remove from the oven and allow the pie to cool completely—preferably overnight—to ensure it sets properly.

Slice into wedges and serve with a generous dollop of whipped cream or a scoop of vanilla ice cream. This pie is delicious at room temperature but even better chilled.