I use a food processor to blend this all together because I feel like it can handle the frozen bananas better than my cheap mixer, but you know your appliances better than I do.
Don't use peppermint extract. It's not the same thing.
Start with 1 tsp of agave nectar and see if you want it sweeter before adding the second.
I know there are lots of folks out there with kids that are sensitive to food coloring, so feel free to skip it. It doesn't change the taste, it's just there for fun.