In a medium bowl, mashed the overripe banana.
Place the chocolate chips in a microwave-safe bowl.
Put the bowl of chocolate chips into the microwave for 30 seconds on high power. Remove the bowl from the microwave and stir the chocolate. Place the bowl back for another 30 seconds on high power. After this, keep microwaving the chocolate chips on high power for 10-second increments, stirring in between every time until the chocolate is smooth and fully melted.
To melt chocolate on the stovetop, place the chopped chocolate in the top of a double boiler over barely simmering water. This method keeps the chocolate away from direct heat, which allows it to melt at a low enough temperature to prevent scorching and separating.
Add almond butter, melted chocolate, and vanilla to the mashed banana and whisk to combine.
Transfer to a parchment-lined loaf pan (or 8×8” baking dish).
Freeze until firm (~1-2 hours). Slice and enjoy (makes 16 pieces). Store leftovers covered in the refrigerator for 1 week or in the freezer for up to 2 months.