Preheat your oven to 350°F and line your muffin tins with muffin liners.
In a large mixing bowl, whisk together the almond flour, granulated brown sugar sweetener, cocoa powder, baking soda, and salt until well combined.
Next, add the eggs, Greek yogurt, and vanilla extract to the dry mixture.
Mix well until the batter is smooth and combined.
Evenly pour the batter among the 12 muffin cups, filling each about 3/4 of the way complete.
Place the muffin tin in the oven and bake for approximately 20 minutes, or until a skewer inserted into the center comes out mostly clean.
Remove the cupcakes from the oven and let them cool for 10 minutes.
In a mixing bowl, beat the softened butter until creamy. Add the sugar-free powdered sugar, cocoa powder, and vanilla extract. Slowly mix in 1-2 tablespoons of milk of choice until you reach your desired frosting consistency.
Once the cupcakes are completely cooled, pipe or spread the chocolate frosting on top. Enjoy!