Combine all the ingredients together (except the spring onions and tofu) in a blender.
Arrange tofu cubes into one layer in a glass baking pan. Pour the blended mixture over the tofu. Lightly press sauce into the tofu with a spatula or hands. Let marinate for a few hours or overnight.
Preheat oven to broil. Broil about 5 minutes, turn the tofu and broil 5 more minutes. Serve hot with chopped spring onions for a garnish.