Place the mushrooms on a baking sheet, drizzle with olive oil and chopped thyme. Squeeze over fresh lemon juice, add black pepper and a few slithers of garlic. Bake in 200℃ oven for about 10 minutes
Meanwhile add the spinach to a frying pan and wilt gently
After 10 minutes remove the mushrooms from the oven, top with the wilted spinach and slices of mozzarella. Return to the grill to soften and melt/brown the cheese.
Serve on slices of toasted sourdough bread with the juices from the baking sheet. Drizzle with balsamic vinegar.