Tofu & Mushrooms In Mustard Sauce

• 3 green onions
• 2 vegetable bouillon (cubes)
• 950 gr tofu
• 120 ml water
• 80 gr button mushrooms
• 65 gr flour
• 60 ml vegetable oil
• 45 ml soy sauce
• 30 ml gray poupon mustard
• 1 gr pepper