Line a mini muffin tin with mini paper liners and set aside (see notes). Add coconut butter container to a large bowl filled with warm-hot water to melt while you prep the other ingredients.
If using the coconut oil and powder method, melt your coconut oil and set aside to cool slightly. Then add carob or cacao/cocoa powder to cooled coconut oil and stir to combine. Or if using the chocolate chip/chopped chocolate method, melt chocolate either in a double boiler or by heating in 30 second intervals in the microwave.
To your chocolate mixture add peppermint extract or essential oil, maple syrup, salt, and cacao nibs if using, then stir to combine.
Using a small spoon, pour enough chocolate into your paper liners to just fill the bottom of each cup. You want to only use half of the chocolate mixture to fill the bottoms, so err on the minimal side. Swirl the pan so the chocolate fills in the edges and partly up each side of the liners. Transfer pan to the freezer to set while you prepare the filling.
In a small bowl mix melted coconut butter and peppermint extract or essential oil until combined. Remove pan from freezer and split coconut butter evenly between each cup. Transfer pan to the freezer for another 5 minutes to set.
Remove pan and cover all cups with remaining half of chocolate. Shuffle or bang pan on the counter to help the chocolate settle, then transfer pan to the freezer to set one more time, about 10 minutes. Once set, store cups in refrigerator until ready to eat.
Cups are best enjoyed chilled or at room temperature. They will keep for a week or two in the refrigerator or a 1-2 months in the freezer.