Sift together cake flour, granulated sugar, baking powder, and salt.
Stir in vanilla, egg, buttermilk, and melted butter until just mixed (do not overmix).
Bake at 425 degrees for 4-5 minutes (watch carefully to not overbake).
Let sit to cool before popping out.
Unwrap caramels and place in microwave-safe bowl with milk and 1/4 teaspoon salt. Microwave at 25-second intervals, stirring in between until fully melted.
Carefully dip doughnuts into caramel and set on parchment paper. Top quickly with toasted coconut.