I'm just about to have a finest pork sausage buttie made with freshly sliced thick white bread, but what condiment should I have with it? I'm thinking brown sauce, tomato sauce or English mustard... I'm even considering Béarnaise sauce, but that'd be a bit weird, wouldn't it? Also, would fried mushrooms and tomatoes "go" on a sausage buttie? What would be _your_ ultimate sausage buttie?