1. Preheat an oven to 350 degrees F. Grease and flour a 9-inch square baking dish. stir 1 cup flour, the baking powder, and salt together in a mixing bowl.
2. Beat the shortening and 1/2 cup sugar with an electric mixer in a large bowl until light and fluffy. Beat in the egg and vanilla, Pour in the flour mixture alternately with the milk, mixing until just incorporated. Pour the batter into prepared pan, then sprinkle evenly with blueberries. Combine 1/2 cup sugar, 1/3 cup flour, cinnamon, and butter in a bowl with a fork until crumbly and evenly mixed. Sprinkle evenly over the blueberries.
3. Bake in the preheated oven until a toothpick inserted into the buckle comes out clean,and top is golden. about 45 minutes Allow to cool before serving warm.