01 -
Set your oven at 350°F. Smear butter on a half-sheet pan, lay down parchment, and butter that as well.
02 -
Combine flour, salt, and baking powder in one bowl.
03 -
Beat sugar and butter together until fluffy. Add eggs one at a time, mixing thoroughly, then stir in vanilla. Switch between adding the dry ingredients and buttermilk and keep mixing as you go.
04 -
Pour the batter onto the sheet pan and smooth it evenly. Bake it for 15 to 20 minutes until the edges lightly brown. Cool for 10 minutes, then chill it in the fridge for 20 minutes.
05 -
Blend the softened butter and marshmallow cream together until silky. Add the vanilla and powdered sugar, beating until smooth.
06 -
Cut the cooled cake into heart shapes using a 4-inch heart cutter. Pipe filling onto half of the hearts, top them with the other halves, and freeze the filled cakes for an hour.
07 -
Heat your candy melts with the coconut oil until smooth. Dunk the frozen cakes into the coating, then chill them for 15 minutes to set.
08 -
Use the melted white chocolate to swirl designs on top of the coated hearts. Pop them back in the fridge until the decorations are firm.