PREHEAT oven to 375°F.
GREASE a 10-inch cast-iron skillet with butter.
COMBINE strawberries, 1/4 cup granulated sugar, lemon juice, and cornstarch in a medium bowl.
SET ASIDE strawberry mixture for 15 minutes to release juices WHILE preparing the rest of the ingredients.
WHISK flour, cornmeal, remaining 1/2 cup granulated sugar, and baking powder in a large bowl.
ADD butter.
ADD salt.
CUT butter into flour mixture with a pastry cutter or two knives until butter is incorporated.
SET ASIDE flour mixture.
WHISK egg and milk in a small bowl.
STIR egg mixture into flour mixture.
SET ASIDE batter.
SCRAPE strawberries and juices into skillet.
DROP batter by the spoonful onto strawberries.
BAKE 30 to 35 minutes or until cobbler is golden brown.
COOL for about 15 minutes.
BEAT heavy cream and confectioners' sugar with an electric mixer until cream is thickened.
SET ASIDE whipped cream.
SPOON cobbler into serving dishes.
TOP cobbler with whipped cream.