“Too many” kinda sounds right to my ear because beans is plural, but the second logically seems right because its served by volume and is not ‘countable’ as ordinary (non-destroyed) beans might be.
“Too many” kinda sounds right to my ear because beans is plural, but the second logically seems right because its served by volume and is not ‘countable’ as ordinary (non-destroyed) beans might be.
“Too many” if you’re referring to the beans themselves. “Too much” if you’re referring to refried beans as a dish you have been served.
Edit: just remember: “too many” as reference to a quantity of things, “too much” as reference to a volume or a quantity/amount of a thing. In this case, the “thing” was the dish being served (refried beans). Since it was the dish, itself, being considered (not each individual bean) the phrase was being dealt with, grammatically, as one whole unit— a dish that was served to you, of which you had too much.