preheat the oven to 350F
Toss Blue berries, lemon juice, 2 Tsp sugar and a pinch of salt in a medium bowl.
using your hand - crush the blueberries. let them sit
Whisk flour, baking powder, remaining 2/3 cup sugar and the salt. Stir in the milk.
melt the butter in the cast iron pan.
remove the pan from the heat: scrape in the batter.
spread the batter evenly and spoon in the blueberries.
Bake until the cake is golden brown. 45-50 minutes.
serve warm with the cool whip