Is an outside kitchen a "kitchen"? Like a built in grille with a sink, out on the lanai. Do you really need two 20a circuits serving a counter top that might only be 3' wide? I suppose you could tap them off the existing kitchen circuits and be legal but is it really necessary?
Kitchen. An area with a sink and permanent facilities for food preparation and cooking.
The ones that I have seen were done just like an 'inside' kitchen. The architects provided the requirements, or the EC just 'followed the code'.
FYI, none were 'only 3' wide'. Most are outrageous IMHO, and keep in mind NJs climate.
As to NEC requirements, by the definition, "area" could be interior or exterior. Eliminate the sink, and it's mot a 'kitchen', even thou a micro, grill, fridge, wine cooler, keg-a-lator, etc. are all there.
I did one of those poolside BBQ/kitchen islands once. I came off the pool equipment subpanel (which was fed from a 50A GFCI breaker) and just brought 2 - 20A circuits out and put a regular outlet on each end of the counter space with one additional outlet under the counter for a mini fridge. I doubt anything more than a blender ever got plugged in out there.