When cooking grains with vegetables, should I cook them together or separately For example, if I would like to make quinoa with mixed vegetables, should I:
(a) Cook the vegetables, add the quinoa and stock, and simmer; or
(b) Cook the quinoa in one pan, cook the vegetables in another pan, then mix them together?

Which of these is ideal to get the most nutrition, or does it not matter? Will simmering them together make it more tasty? Also, would your answer vary for different grains, for example rice, or bulgur wheat?
I would cook them in different pots.

Most of the time they will take different time to cook; heck, even different vegetables take different time to cook, so cook the vegetable in batches.