With the help of a chopping board and a sharp knife, cut thin pieces of the orange zest, walnuts and peanuts in small pieces, the smaller the better. You can use a food processor too. Mix them in a bowl. You can also add a spoonful of rum (optional). Reserve.
Melt chocolate and coconut oil in the microwave for about 5 to 10 seconds. A portion of the chocolate will start to melt, remove it from the microwave oven and stir it gently with a spoon and put it back in the microwave oven for another 5 seconds. Repeat this as many times as deemed necessary. Also, you can use a Bain-Marie (or a double boiler) to melt the chocolate if necessary.
When all of the chocolate and coconut oil is finally melted, add the sweetener, cinnamon powder and nutmeg and mix them well.
Add the nut mixture (walnuts and peanuts) to the melted chocolate and mix them well.
Finally, when the mixture is well integrated, pour it in each silicone fat bomb mold to fill them up completely.
Refrigerate for about 20 minutes and unmold. Serve and store the rest in the fridge for next use.