A quick and easy meat-free lunchtime bite!
Put a heavy-based frying pan, or a griddle pan, over a medium heat to heat up.
If you are using one large slice of sourdough, cut it in half.
Generously butter both pieces of bread on one side only.
Place one piece of bread butter side down and spread a thin layer of mustard over it. Top with half the grated cheese.
Add the slices of ham, then the remaining cheese. Top with the remaining piece of bread, butter side up.
Place the sandwich in the hot pan. You can either now press the sandwich down firmly with a spatula, or place a weight on it, such as another, smaller pan with something heavy in it. The idea is to press the sandwich down in the pan so it gets maximum crispness and the heat travels quickly to the centre, melting the cheese.
After about 2 minutes, use a spatula to carefully turn the sandwich over and press it down again.
Grill the other side for a minute or so until both sides are golden brown and the cheese is oozing.
Transfer to a plate and serve straight away with tomatoes and slivers of red onion.
Serving Size 1