1stick butter1/2 cup melted unsalted butter, plus additional for greasing the skillet
1 1/2cupsall-purpose flour
2teaspoonsbaking powder
1teaspoonkosher salt
2cupssugar
1cupwhole milk
12ouncesfresh blackberries
1cupboiling water
Rum Saucerecipe follows
Rum Sauce
2tbspbutter
1tbpscorn start
1/2cupsugar
1/2cupwhole milk
1/2cupheavy whipping cream
3tbspwhite rum
Instructions
Preheat the oven to 350 degrees F and butter a 12-inch cast-iron skillet.
Whisk together the flour, baking powder, salt, 1 cup sugar, the melted butter and milk in a large bowl. Beat well, then pour the batter into the buttered cast-iron skillet. Top with the fresh blackberries, sprinkle with the remaining cup sugar, then pour the cup boiling water over the top. Carefully, transfer the skillet to the middle oven rack.
Bake until the filling is bubbling and the cobbler topping is golden, 55 - 60 minutes. Serve with warmed rum sauce on the side if desired.
Rum Sauce
Melt butter in a small saucepan over medium heat. Mix together the sugar and cornstarch, and stir into the butter. Pour in milk and cream, and cook stirring frequently until the mixture begins to boil. Continue cooking until thick, stirring constantly. Remove from heat, and stir in rum. Serve warm.