spinach, mushroom and tofu soup

recipe from Chinese Vegetarian Cooking book

Ingredients
1 tbs cooking oil
2 cloves garlic, smashed with side of cleaver, skin removed
2 slices of ginger
300g fresh chinese spinach (bayam), washed and plucked
800ml (3 1/4 cups) vegetable stock or plain water
1 cake soft tofu, cubed
1 cup canned button mushroom, halved
2 tsp sesame oil
salt & pepper to taste

Method.
1. In a medium-sized saucepan, heat oil until smoking hot, then add the garlic and ginger and stir fry quickly for 30 seconds. Add the chinese spinach and stir-fry for a about 2 minutes.
2. Add the vegetable stock (or water), tofu, button mushrooms and cover. Bring to  a full boil, then lower heat and simmer for 2 to 3 minutes.
3. Turn off heat, stir in sesame oil and salt and pepper to taste, then transfer to soup tureen and serve.