Add the peanut butter, maple syrup and coconut oil to a small pot over a low heat. Mix until smooth and well combined, then remove from heat and stir in the vanilla extract.
Add the peanut butter mixture to the bowl with the cereal and stir until the cereal is completely coated. Divide this mixture equally between each of the prepared muffin tins, filling about ⅔ of the way up the side of the cup. Then gently flatten the top so it is even and compact.
Now make the chocolate topping by placing the chocolate into a glass bowl and microwaving it on high in 30 second intervals, stirring in-between, until the chocolate has completely melted. Alternatively, melt the chocolate in a small non-stick pot over a very low heat.