Line 12 mini muffin tins with liners- parchment works the best.
In a large sauce pan, combine coconut oil, cacao powder, maple syrup, and salt. Heat over medium heat and whisk until fully combined. As soon as it starts to boil, turn off the heat. Spoon about 1 tablespoon into each liner. Once they all have some chocolate in them, tilt the pan gently in a circle to get the chocolate to go up the sides a little. Leave the remaining chocolate in the pan for the top. Place in the fridge for 10-15 minutes- until they are fully hard.
While they are chilling, make the filling. In a small bowl, combine nut butter and the maple syrup. Stir until well mixed. Remove the chocolate from the fridge and fill each one with a little of the nut butter mixture until all the mixture is used. Spoon the rest of the chocolate over the nut butter, making sure to completely cover it. *If the chocolate mixture has hardened, turn the heat on low until it’s smooth again.
Place cups back in the fridge and let them chill for 20 minutes, or until they are completely hard. To easily remove cups, run a butter knife around the edges then peel off the liner. Store in the fridge or freezer.