Arrowroot Substitution

1 Tbls. flour
plus
1 1/2 tsp. cornstarch
can be substituted for 1 1/2 teaspoon arrowroot.

Flour, Self-Rising Substitution

1 cup all-purpose flour
plus
1 1/2 teaspoons baking powder
plus 
1/2 teaspoon salt
can be substituted for 1 cup self-rising flour.

Flour, Cake Substitution

1 cup
minus
2 tablespoons all-purpose flour
can be substituted for 1 cup cake flour.

Flour, as a thickener Substitution

1/2 tablespoon cornstarch
or
potato starch
or
rice starch
or
arrowroot starch
or
1 tablespoon quick-cooking tapioca
can be substituted for 1 tablespoon all-purpose flour.

Flour, all-purpose Substitution

Self rising flour
minus
the salt in yeast bread
can be substituted for all-purpose flour.
Self rising flour
minus
the salt and baking powder can be substituted for all-purpose flour in quick bread recipes.
1 cup
plus
2 tablespoons cake flour
can be substituted for 1 cup all-purpose flour.

Cornstarch Substitution

2 tablespoons all-purpose flour
or
2 teaspoons arrowroot starch
can be substituted for 1 tablespoon cornstarch.