British self-rising flour does not include the salt as American self-rising flour, worth keeping in mind for regional recipes.
For British recipes calling for self-rising flour, Nigella Lawson recommends adding “2 teaspoons of baking powder to each cup (150g) of all-purpose (plain flour). We would not add baking soda (bicarbonate of soda) unless the recipe states specifically that it is added separately to the self-rising flour.”
“if you are looking to replace self-rising flour in a US recipe then you need to add 2 teaspoons of baking powder and 1/2 teaspoon salt to every cup of all-purpose flour.” 1
1. Self-Rising Flour Substitution | Ask Nigella.com | Nigella Lawson. (2023). Retrieved 26 June 2023, from https://www.nigella.com/ask/self-rising-flour-substitution
