1. Preheat oven to 375°F (190°C) and grease a 9-inch quiche pan.

2. Lightly toast sourdough slices and arrange them along the bottom and sides of the pan.

3. Heat olive oil in a skillet over medium heat, add garlic and sauté for 30 seconds.

4. Add mushrooms and cook until golden brown, 4 to 5 minutes.

5. Add asparagus and cook until bright green and tender, about 2 to 3 minutes, then season with salt and pepper and set aside.

6. In a bowl, whisk eggs, milk or cream, salt, pepper, and herbs until smooth.

7. Spread sautéed vegetables over the sourdough base and pour the egg mixture over them.

8. Sprinkle cheese evenly on top of the quiche.

9. Bake for 35 minutes or until the edges are golden and the center is set.

10. Let quiche rest for 10 to 15 minutes before slicing and serving.