Sure, buying a premade pouch or smoothie probably appears simpler–if not less futile–than making your own concoction twice a week, but if I told you could make something better in five minutes—or ten, if you want your kid(s) to help make it—and meet 85% of a day’s fruit and veggie intake in one serving you’d do it, right? This is that right one.
Dealer's choice here: pouch, bottle, cup, etc. If you're working on improving your child's ability with an open cup, this is a good one for practice.
Smoothies are, by their nature, endlessly adaptable. This one is no exception: you can swap spinach for kale; watermelon for the mango or ; increase the vegetable ratio--try adding celery!--and decrease the fruit; et al.
*Around two years of age I got my son involved in the process by having him separate the spinach leaves; by three, I hope to have him help me with peeling and pouring.