Add the mashed avocado and cacao powder into a large food processor and blend until smooth and combined, stopping to scrape down the sides as necessary.
Add in the champagne, agave (if using) and a pinch of salt and blend until smooth and combined.
Place the chocolate in a microwave-safe container and heat using half power, and 30 second cooking intervals, stirring between each interval, until smooth and melted.
Add the melted chocolate into the food processor and blend until smooth and combined, scraping down the sides as necessary.
Scrape the mixture into a medium bowl, spreading out evenly. Cover and refrigerate until set, about 2 hours - overnight.
Line a baking sheet with parchment paper and fill a shallow plate with sides with extra cacao powder. Roll the truffles into lightly heaping 1 Tbsp sized balls (I used a cookie scoop, and made them just a little smaller than the full cookie scoop.) Roll around in the cacao and place onto the prepared pan. *
Do not roll them in sprinkles like in the photo, as the sprinkles do melt.*Truffles will be a little soft, so your hands will get a little messy, but it's worth it!Store truffles in the refrigerator if not serving right away.