A book "the 50 best fudge recipes" advise from scaling up the recipes. Does anyone know of any commercial scale fudge recipes or can the recipes simply be increased proportionately?
They advice against scaling, because cooking a batch twice as large will take more than twice as long. Nothing terrible will happen if you scale a recipe, but you will likely spend hours waiting by the stove for your fudge to reach the correct temperature. It's faster to just cook several small batches one after the other, or making several in parallell in different pots.