My recipe calls for unsalted butter but I only have salted butter on hand. Will this be a problem in the taste or consistency of my fudge?
Provided the butter is not too salty, it should not affect the consistency or setting, but it will add an extra flavour dimension to the fudge. I don't know what ratios you will be using, but salt and sometimes chilli is added to chocolate to add extra flavour. Personally, I would not find a little bit of salt to balance out the sweetness unpleasant, but that would very much depend on the amount in the butter. Too much would be overpowering.