Blueberry Upside Down Cake
["4 Tbsp. butter, melted plus more for souffle dish", "1/3 c. plus 3 Tbsp light brown sugar", "1 1/2 c. blueberries, picked over and cleaned", "1/4 c. cake flour (not self-rising)", "1 tsp. baking powder", "1/4 tsp. salt", "1 large egg", "1/4 c. milk, room temperature"]
["Heat oven to 350\u00b0.", "Butter a 1 quart, 5 1/2 inch diameter souffle dish.", "Pour 2 Tbsp. melted butter into the souffle dish. Sprinkle 3 Tbsp. brown sugar over butter.", "Scatter 1 c. blueberries over sugar.", "Set aside."]
["butter", "light brown sugar", "blueberries", "cake flour", "baking powder", "salt", "egg", "milk"]