Place all —avocados, agave nectar, cocoa powder, almond butter, lemon juice, and optional extract—into the bowl of a food processor or a high-speed blender. 2.
Blend on high for 3 to 4 minutes, scraping down the sides of the bowl occasionally, until the mixture is completely smooth, creamy, and no green specks remain. 3.
Divide the mousse into four serving bowls.
Serve immediately for a softer pudding-like texture, or chill for at least 30 minutes for a firmer mousse.
Adjust sweetness to your liking. Start with a little less agave, taste the mixture, and add more if needed before the final blend.
Don't skip the lemon juice! It brightens the chocolate flavor and prevents the avocado from browning, keeping the color rich and deep.