I always make my own self-raising flour, because I can’t get self-raising flour where I live. It is also so much easier to make it yourself. This is the recipe that I use:
215 g (2 1/2 cup) all-purpose flour (plain flour)
2 1/2 tsp baking powder
1/4 tsp fine salt
Place all the ingredients in a large bowl and give it a good whisk. Sift the self-raising flour 2-3 times and it is ready to use.
TIP! Make a large portion of self-raising flour and store it in a air tight container. Remember to sift the flour before use.