Flour, is one of ingredient should be stocked in all the time but in the market got many kind of flour even the recipe did calling for different flour. Think again, back to the period of Victorian and Edwardian, the household during that time only have basic flour; therefore they could bake, cook, literally everything.
All-purpose flour is the most versatile flour ever. Indeed it is a basic flour you will need.
If your recipe calling for cake flour, self-raising flour, etc
For 125g / 1 cup of cake flour:
Substitute 15g (2 tbsps) of cornstarch/cornflour + 109g (¾ cup + 2tbsps) of all purpose flour
The Substitution: 1 part cornstarch + 7 parts of all-purpose flour
For 150g/1 cup/6oz of self flour:
Self-raising flour contains baking powder but as baking powder will expire after a period of time you need to use up self-raising flour more quickly than plain flour.
In US self-raising flour contains around ½ teaspoon of salt per cup which can lead to some of the recipe tasting a little too salty in the flour.
Substitute with 150g/6oz/1 cup of plain flour and add in 2 teaspoons of baking powder then sift the flour and baking powder together into a bowl before using, to make sure the baking powder is thoroughly distributed. If your recipe call for buttermilk, cocoa or yogurt then add in ¼ teaspoon of bircabonate of soda (baking soda) as well as baking powder.