Preheat oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan.

In a large bowl, cream together the softened butter and sugars until light and fluffy. Beat in eggs one at a time, then stir in the vanilla extract, lemon zest, and lemon juice.

In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Fold in the sour cream and blueberries.

Pour batter into the prepared pan. In a medium bowl, combine the crumble topping ingredients using a pastry blender or your fingers until the mixture resembles coarse crumbs.

Sprinkle the crumble topping evenly over the batter.

Bake for 40-45 minutes, or until a wooden skewer inserted into the center comes out clean. Let cool completely before glazing.

For the glaze, whisk together the powdered sugar and lemon juice until smooth. Drizzle over the cooled cake.