Preheat oven to 350°F.
In a bowl, toss blueberries in sugar, cornstarch, lemon juice and zest, vanilla, and a pinch of salt. Set aside and let marinate for 20 minutes.
In a separate bowl combine dry ingredients for crust. Flour, sugar, baking powder, and salt. Whisk.
Work butter into dry ingredients until combined. Don’t overwork, it doesn’t have to be perfect.
Once combined, stir in milk and egg until a dough forms.
Bring the berries back and pour into a 10" cast iron.
Top the berries with small scoops of your crust dough.
Brush the tops of the dough with egg wash.
Bake for about 40 minutes or until the crust is golden brown and the filling is nice and bubbly.
Take it out of the oven and let it cool for 10 minutes.
Top with your favorite ice cream!
