Peel and pit the avocados, and cut them into small pieces.
Peel and slice the bananas and mix them with the avocado pieces.
Use an immersion blender to make a puree of the bananas and avocados.
Add cocoa powder to taste. I've given you a general guideline of how much cocoa powder I usually add, but I like dark chocolate and love a strong chocolate flavor in these sorts of desserts. Continue to blend with the immersion blender to fully combine the ingredients, tasting it occasionally as you add in cocoa powder to taste.
For a sweeter popsicle, add in some sweetener of your choice. Stevia is a good choice for a low carb version. You can also add in honey or maple syrup.
If you choose, you can lighten up the flavor with a dash of almond milk, coconut milk, or a dash of cream. Blend until all ingredients are fully combined.
Pour or scoop the mixture into popsicle molds. Add popsicle sticks and freeze for several hours until frozen solid.
Remove the popsicles from the freezer. You may need to run warm water over the outside of the molds to loosen the popsicles. Remove the popsicles from their molds and serve immediately!
Don't try making this recipe in a Zoku popsicle maker if you have one. It has too much fat and not enough sugar, and it will likely get stuck. (Don't ask me how I know that!) ;)