Question: does plain flour and baking soda make self raising flour?
Answer: “It is fairly easy to make your own self-raising flour. Just add 2 teaspoons of baking powder for each 150g/6oz/1 cup plain flour. ... Well, for each tsp of baking powder you need for a recipe, you can replace it with a 1/4 tsp of baking soda and 1/2 tsp vinegar.