I've made heaps of muck-ups over the years, but my most recent was to get corned beef mixed up with a roast of beef (admitedly the label had worn off). I boiled the roast and I can tell you, there is nothing much worse than boiled beef with mustrard sauce
I can remember at school when we had cooking lessons, that one of the girls when told to soften butter over hot water, poured the hot water INTO the butter and had to throw the whole lot away. And another girl tried to flush a disastrous meringue attempt down the loo but it persisted in floating on top. *whatever has that poor girl got wrong with her???? *