Preheat the oven to 350ºF and line a muffin tin with parchment or silicone liners.
In a large bowl, whisk together the coconut flour, sweetener, cocoa powder, protein powder, baking powder, and salt.
Stir in the eggs, butter, and vanilla extract until well combined.
Stir in the coffee about ¼ cup at a time until the batter is thick but easily scoopable.
Divide the batter evenly among the prepared muffin cups.
Bake 20 to 25 minutes or until the tops are just firm to the touch.
Remove from the oven and let cool completely in the pan.
In a small bowl, stir together the hot water and espresso until coffee dissolves. Set aside.
With an electric mixer, whip the cream until it forms stiff peaks. Set aside.
In a medium bowl, beat the butter, cream cheese, and sweetener together until creamy.
Add the coffee mixture and beat until combined.
With a rubber spatula, fold in the whipped cream carefully until well combined.
Spread the frosting on cooled cupcakes with a knife or offset spatula, or pipe on with a decorating bag.
