I have a recipe that i want to try but i dont have cake flour. I had read somewhere that if you dont have cake flour and want to use all purpose all you would have to do is add a little bit of baking soda. If this is true, does anyone know how much baking soda to add if the recipe is 1 1/2 cups cake flour? Thanks!

When I need "cake flour" I substitute one table spoon all purpose flour for one table spoon corn starch for every cup of flour. Works great for me.

@julia1812 ‍ Thanks! Ill try that. The only thing is i didn't understand how that is done exactly, So if my recipe calls for one and a half cup of cake flour how much all purpose flour and cornstarch would i need. Sorry...im a bit slow today, that went over my head lol. 

Okay...take one and a half cups all purpose flour instead. Then take out one and a half table spoons from the all purpose flour and put one and a half table spoons corn starch into the (now almost) one and a half cups all purpose flour. Sorry! I don't know if that makes sense now? So basically use a flour bit replace some of it with corn starch. 

Some recipes call for baking powder, some for soda, some for a combination.  Just use whatever is indicated for that specific recipe.

Thanks! Yes now i got it! =) hehehe This particular recipe doesn't have Baking Powder or Baking Soda in it so im not sure ...

No raising agent at all? That's strange. ..

All my recipes have raising agents. Normally between 1-2tsp baking powder for about 6 cups of batter.

I think the best is to post the recipe here otherwise people won't be able to help.

The Recipe is this

6.5 Tablespoons of clarified beurre noisette = (which is melted and browned butter)

1 1/2 teaspoons Vanilla

2 Tablespoons  Orange zest

1 1/2 cups Cake flour

3/4 cups minus 2 teaspoons Cornstarch

9 large egg whites

1 1/4 cups Sugar

3/4 water

This recipe is a White Genoise recipe from the Cake Bible book. 

I'm not sure if this is going to work. A Genoise or a sponge cake is very delicate because it relies on the lift of the egg whites for leavening. Cake flour is normally used because of its lightness. I've only seen cake flour used in these kinds of cakes but make sure and report back if it does work!

The recipe I use is from  Food.com  and Joy the baker

1. 
   
2. For every 1 cup of flour remove 2 Tbsp of flour.
3. Now add 2 Tbsp of Cornstarch for every 1 cup of flour. ... 
4. Sift 5-6 times and it's ready-to-use cake flour