I would think make whatever shakes you would want. A few different flavors of protein powder, milk/water, some fruit, peanut butter, veggies if you want (though I've never tried adding them honestly), oats possibly, olive oil, Greek yogurt. Could buy bulk maltodextrin powder or something.
Could very easily mix and match all of the above to get dozens of different flavors and macros. Some fruit flavored protein, milk, Greek yogurt, ice and whatever fruit you want tastes awesome. Would be very easy to get enough calories in.
EDIT: Obviously throw your desired ingredients listed above into a blender. I doubt it would work well if you just tried a shaker cup to blend some of these.