Preheat oven to 350 degrees F (175 degrees C). Grease a baking dish.
Combine huckleberry juice, 1/2 cup sugar, and 2 tablespoons flour in a saucepan; bring to a boil. Cook and stir until thickened, about 5 minutes. Stir in huckleberries; cook until tender, about 5 minutes. Pour into the greased baking dish.
Mix 1 1/2 cup flour, 3 tablespoons sugar, baking powder, and salt together in a bowl. Cut in shortening until mixture forms coarse crumbs. Mix in milk and egg until dough comes together. Spread dough over huckleberry layer.
Bake in the preheated oven until top is golden brown, 35 to 40 minutes.