Pediasure

[Aligater]

is anyone elses baby/toddler on this can you cook with it at all?

[Early Kids]

DS2 used to be on it, it can be used just like formula, however keep in mind it is flavoured... so may not work with some meals where milk is used in cooking lol.

[RainbowBrite]

My little man is on it. Our is a vanilla flavour so I wouldn't cook with it in savoury items...maybe sweet ones (like creamed rice)
Have you thought of cooking with cream, that is what I tend to do to add the calories.
I add it to mashed spud, creamy pastas etc
Or you can use powdered milk but add an extra scoop of milk powder and use that for cooking.