Croque Monsieur Brunch Bake



8 slices white bread
cooked ham (enough to make 4 sandwiches)
slices of gruyère cheese (or any tasty cheese of your choice – enough for 4 sandwiches)
6 eggs
370 ml/12.5 fluid ounces milk
1 heaped teaspoon mustard (I used Dijon)
half a small onion, chopped finely
2 garlic cloves, crushed
salt and pepper
about 150 grams/5 ounces cherry tomatoes, halved
grated cheese e.g. mozzarella for sprinkling
a handful of fresh chopped parsley