Turn on the oven to preheat to 180 degrees. Cut off the stems of mushrooms almost completely and put the caps down on a baking sheet. Place 2 sprigs of thyme on each cap and sprinkle all the mushrooms with 2 tablespoons of olive oil. Place the baking sheet in the preheated oven and cook for about 15-20 minutes.
Meanwhile, wash the asparagus and blanch until soft. Cut each stick in half. Fry the bread slices in a roaster or toaster, and place the same amount of asparagus on each slice. Then remove the mushrooms from the oven and place one on each piece of bread.