How do you get a good texture/consistency in a smoothie bowl?

I'm thinking specifically for Booster Juice's smoothie bowls. They just use ice, but when I blend mine thin enough to eat it melts too quickly and I basically end up with cold soup. I know you can use a thickener, but I'm allergic to bananas and avocados, and I'm just basically trying to recreate Booster Juice's green smoothie bowl.

bon appetit