For cupcakes:

Preheat the oven to 176 ° C and prepare 2 cake pans with paper cups (liners). Place all the dry ingredients in a mixer and mix until combined. Heat the water, butter and instant coffee on the stove until melted. Add the eggs and buttermilk to the dry ingredients and turn the mixer on low, pouring in the melted butter and coffee mixture. Pour 1/4 cup batter into prepared liners. Bake the cupcakes for 18-20 minutes. Cool for about 15 minutes before removing from the pans.

For the glaze:

In a water bath or double-bottomed saucepan over medium heat, mix the egg whites and sugar together. Heat to 55 - 60°C and continue stirring all the time until the sugar is completely dissolved (about 5 minutes). Pour the mixture into a mixer and beat on low until frothy. Increase the speed slowly until the mixer reaches high speed. Continue mixing the mixture until glossy peaks appear. Add the butter (one tablespoon at a time while the mixer is on low/medium speed). The mixture will begin to puff up and then become lumpy. Add the vanilla extract. Continue beating on high until a homogeneous mixture is formed. Remove the beater and place the mixture under the paddle of the mixer (one with a spatula end is preferable, but not necessary). Beat on low speed to release the air until it becomes a smooth and glossy buttery mass. Fill a plastic bag with the frosting and cut a dime-sized hole in the end. Add the frosting to the cooled cupcakes and place in the freezer to firm up.

For the shell:

In a medium microwave-safe bowl, melt the chocolate and coconut oil together in 30 second intervals, stirring in between. Let the mixture cool for 15 minutes. Dip the cooled cake into the chocolate mixture. Lift and swirl the cupcake to remove excess chocolate. Continue this step with the remaining cupcakes.