Preheat oven to 375°F.
In a 9-10 inch cast iron skillet, mix blueberries, brown sugar, and lemon juice. Set aside.
In a small bowl, mix flour, baking powder, and salt. Set aside.
In a medium bowl, cream butter and white sugar until fully mixed, light and fluffy. Beat in egg and vanilla extract. Gradually add flour mixture, stirring until combined. Batter will be sticky and pretty thick. If doughy, you need to mix more.
Layer batter using rounded tablespoons over blueberries, covering as much of the blueberry filling as possible. It's OK if there are "holes."
Bake for 35-40 minutes, until topping is golden brown. Let cool for 5 minutes, drizzle with almond frosting, and serve warm with vanilla ice cream.