Set up a double boiler.

Line a 5x5 inch pan with parchment paper or foil.

Chop the chocolate bar and mash the avocado.

Combine the chopped chocolate, mashed avocado, and coconut oil in the double boiler.

Stir constantly until the chocolate and coconut oil are melted and smooth.

Remove from heat.

If using stevia, add it now and stir to combine.

Spread the fudge into the prepared pan using a rubber spatula.

Add any desired toppings (sea salt, toasted nuts, etc.) and press them into the top.

Refrigerate for 2-3 hours before cutting.

Run a sharp knife under hot water and slice the fudge into equal pieces.

Keep refrigerated when not eating.