Toss the mushroom slices in a bowl with the olive oil and some of the leaves from the thyme sprigs. Cook them in the griddle pan until soft, lined and golden. Remove from the pan and keep warm
Cook the halloumi in the griddle pan until nicely marked, remove from the heat and set aside with the mushrooms
Dip each slice of brioche in the beaten egg and cook in the frying pan in a little butter until golden on each side. Put two slices on each plate
Mix the remaining thyme leaves with the creme fraiche
Top the brioche with a spoonful of creme fraiche, then add two slices of halloumi and some mushrooms. Add four quarters of a cherry tomato to each and serve with a pinch of chilli flakes and salt to season