Place cacao butter and extract in a small saucepan.
Melt over low temperature.Once fully melted, remove from heat and add in protein powder, nut or seed butter and stevia.
Whisk to combine.Pour into a 13x9 glass pan (no need to line the pan); or one of your choice, and top with a sprinkle of cacao nibs.
If you want to make this recipe more portable, you could use a silicon mold like this animal silicon mold.Transfer to the freezer for 30 minutes to harden.