What would you substitute buttermilk for and also full cream milk powder?
Buttermilk is soured milk by the addition of lactic acid bacteria (these days) traditionally it was the liquid left behind from churning butter. In any event you are looking for a sour tasting "milk" product as a substitute. Traditionally vegan buttermilk is made by adding a tablespoon of vinegar or lemon juice to vegan milk and leaving it to curdle for about ten minutes before adding to your recipe. Thats for baking, I think for like a buttermilk sauce you would add vinegar to liquefied Japanese soft tofu with a tablespoon of soy cream cheese. Full cream milk powder? Dumb question but can you buy soy milk powder? If not there are soy based (vegan) baby formulas out there they might have the exact taste you need. Let me know how you go with this one! (just thought also protein powder? the arbonne vanilla one is rich and creamy but not sure what purpose you would like to use it for).
I buy already marinated tofu. What do you suggest marinading tofu in without having to fry it?
This question comes from my sister who is very much NOT a vegetarian, but curious in different ways of cooking so I will take a little bit longer than I usually would to answer this question. Tofu is like a sponge, it takes on all the flavours of the food you are cooking it with. For a guide on all the different kinds of tofu and how to prepare them please see this post. So you will see by squeezing as much water out of the firm tofu it leaves more room for it to soak up liquids. So you may find you don't need to marinade it at all if you are throwing into a stir fry or curry. If you want to enjoy as thick tofu steaks on their own or marinade to throw on a bbq, use any of your favourite recipes, marinade just like meat. Cover the tofu with the liquid and let sit in the fridge for a couple of hours. I would say dilute marinades meant for meat as tofu takes on SO much flavour they might become too overwhelming and marinades meant for meat are full of acidic ingredients to break down the meat and tenderise it, tofu doesn't need that at all, its just waiting to soak up the love. My favourite is to marinade in half soy sauce, half maple syrup with 4 or 5 cloves of garlic minced, grated fresh ginger, fresh chilli and a dash of sesame oil (enough liquid to cover the tofu steaks). So simple and delicious! I love using this on tofu steaks and cook them in a fry pan for sandwich fillings. This marinade is almost instant so no need to wait!