Lightly beat the eggs, then mix with the milk and a pinch of salt.
Slice the farmhouse loaf into thick slices and dip into the batter.
Fry in the butter until golden on both sides.
In a separate pan, cook the mushrooms in the olive oil until brown.
Add the balsamic vinegar and reduce until sticky.
Spoon over the hot French toast and serve with grated Parmesan.