Mash avocado flesh in a bowl with a fork, ensuring there are no more chunks left. 

Melt 5 oz dark chocolate chips in a microwaveable bowl in 30 second increments, stirring in between each, until smooth. Remove from microwave.

Add melted chocolate to the mashed avocado, and stir until combined. 

Chop remaining dark chocolate chips roughly. Stir the chopped chocolate into the chocolate avocado mixture. 

Stir in Grand Marnier and 1/4 tsp of cayenne pepper. Taste to determine if you would like more heat to the mixture. If so, add another 1/4 tsp of cayenne pepper. Refrigerate mixture for at least 1 hour.

Add cocoa powder to a shallow baking dish or bowl.

Using a tablespoon measurer, scoop out 1 Tbsp at a time of the mixture. Roll each tablespoon into a ball and roll in cocoa powder until covered. Set finished truffle on a separate plate.

Repeat process with the remaining truffle mixture. Serve immediately or keep in the refrigerator until ready to serve.