Prepare 3 shallow bowls with 1/ plain flour, 2/ egg and milk whisked, 3/ breadcrumbs.
For each schnitzel dust in flour, then dip in the egg mix, then finally cover in then the breadcrumbs. When all the schnitzels are covered, place in the fridge until the oil is ready.
In a frying pan melt the butter with the olive oil to a moderate temperature. Gently cook the schnitzels until brown then turn and cook the other side. If cooked at too high a temperature the crumbs can burn and/or fall off.