This is key. You want customers to love your brownie and not be annoyed with getting it into their mouths. If this was my brownie recipe, I would add 25% more flour instead of 100% which you said did not work. Can you bake them in paper cupcake liners? There's no cutting, paper gives the customer something to hold onto, and the individual size may help with baking to a drier consistency.
CraftyCassie, I don't think the problem is using different milk. The amount of fat from 2% or whole milk (for use in a recipe) is negligible. At my shop we had skim and full-fat milk in the cooler, and used whatever milk had the shortest date; there was no difference in product outcome. During the no-fat craze bakers learned that no-fat in a recipe adversely impacted paper liners. But it's a stretch to use that info and think that too much fat will cause paper liners to...
Are you a caker (hobby or business) living in New York's Hudson Valley? The Hudson Valley Baking Society (HVBS) is a regional group based in Ulster County. We meet at BOCES (part of the state education system) and use the commercial kitchen for our member-led workshops. We bake together every December to sell cookie trays and raise money for the regional food bank.
Interested in joining the HVBS? Post a reply here, or send me a PM or email us email@example.com