Quik Help with CUPCAKES! : How do I make self raising flour from plain flour?

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I am about to bake cupcakes, and the recipe says 125 g self raising flour. But there is no such thing as self raising flour in Norway, so what do I do?

Add a tea spoon of Bicarbonate of Soda and one of baking powder. This should help them rise.

1 cup plain flour+1 and a half tsp baking powder+ pinch of salt.

Thanks!