Mango and watermelon are blended together in this light and refreshing smoothie to make this a perfect beverage for a hot summer day. Sep 3, Deliciously refreshing 2-ingredient watermelon smoothie. Fabulous for breakfast or a post-workout snack. Hydrating and invigorating. Jul 13, That's how obsessed I am right now: WORLD'S BEST WATERMELON SMOOTHIE is up in the howwwse, featuring 4 simple ingredients.