Vegetarian Croque-Monsieur with Mushrooms and Goat Cheese

Vegetarian Croque-Monsieur with Mushrooms and Goat Cheese
Ingredients:

2 slices of wholemeal sandwich bread
50 g of button mushrooms, thinly sliced
2 rounds of goat cheese
A few spinach leaves
A little crème fraîche
A little butter
Preparation: