It depends on whether you’re referring to individual refried beans or the dish ‘refried beans’ as a whole.
If it’s the former, it would be ‘too many’ (individual) refried beans.
If it is the latter, it would be ‘too much’ (of) refried beans… Unless you had multiple servings, in which case it would be ‘too many’ (servings of) refried beans.
That is my opinion: as such it is subject to change should further information come to light.
Good Morning Glipglorp! From the Androids and Aliens podcast by the Glass Cannon Network. It was a random bit of world-building that the players latched on to and ran with and it turned into a whole episode.