When something works with no mods, but the 50/50 method doesn't identify the problem it's probably a conflict between two different mods. If one of them is in your first batch of mods and one is in your second, it will work fine with just each batch alone but won't work with both batches together.
Have you run a mod conflict detector on your mod's folder?
The most likely culprits are any mods you use which affect cooking, by the way. I'd remove just those mods which add new recipes (or change existing recipes) and those which make changes to cooking/baking to see if it works fine with only those removed. Then, if it does, I'd add back just one of those mods at a time until I identify at least one of the culprits.
