Vegetarian bbq duck

Ingredients

• 2 tablespoons mushroom sauce
• 1 tablespoon maple syrup
• 1 teaspoon sugar
• 1/2 teaspoon light soy sauce
• 1/2 teaspoon dark soy sauce
• 1/2 teaspoon sesame oil
• 1 teaspoon tapioca flour
• dash of pepper
• 1 - 2 tablespoon water