Cut the cleaned mushrooms into thin slices. Pour oil into a pan and heat it, sauté thinly sliced mushrooms for 1-2 minutes.
Add the balsamic vinegar and sugar, mix well, and let sit for a few minutes until the sugar and balsamic vinegar caramelize. Then add salt and black pepper to your taste. Remove from heat.
Toast thin slices of bread in the oven heated to 200°C for about 4-5 minutes.
Rub one side of bread with garlic (cut in half).
Top bread slices with prepared mushrooms. Bon Appetit!