Sub All Purpose Flour For Cake Flour

Let’s be honest: you’re staring at a recipe that calls for cake flour, and all you have is that dusty bag of all-purpose flour that’s been hiding behind the baking soda since the Obama administration. Don’t panic. You aren’t a bad person, and your cake won’t spontaneously turn into a brick—if you know the secret handshake.

Here’s the deal: cake flour is the delicate, high-maintenance diva of the flour world. It has a lower protein content—around 7 to 8%—which means less gluten develops, giving you a tender, fluffy crumb that practically whispers “I’m worth it.” All-purpose flour, meanwhile, is the rugged generalist, hanging out at about 10 to 12% protein, ready to make anything from pizza crust to murder scene cookies.

The Great Heist: How to Steal Cake Flour’s Vibe

You can absolutely swap all-purpose for cake flour, but you have to trick chemistry into forgetting it’s stronger. The trick is cornstarch. Yes, that box of white powder you only use when you’re making gravy or pretending to be a ghost for a party.

For every one cup of all-purpose flour you want to turn into fake cake flour, remove two tablespoons of that flour and add two tablespoons of cornstarch. Sift it together at least three times. Yes, three. I know it feels obsessive, but cornstarch is a bully to gluten proteins, and sifting is your way of saying, “No, flour, you will not form a tough network today.”

If you skip the sifting, you’re basically making a rubbery pancake. And nobody wants a rubbery pancake that thinks it’s a birthday cake. Trust the sift.

Why This Works (And Why You Shouldn’t Overthink It)

Cornstarch is pure starch with zero protein, so it dilutes the overall protein content of your blend. You’re literally watering down the gluten potential, making your flour behave like a delicate little flower. The math: two tablespoons of flour removed cuts about 1.5 grams of protein, and the cornstarch adds exactly zero grams. Boom—you’ve dropped from 11% protein to roughly 8%. That’s cake flour territory, baby.

Surprising fact: Before the 19th century, bakers used to sift flour seven times for the lightest cakes. Seven times! People had more patience (and worse back health) back then. Three sifts is our modern, rebellious compromise.

Now, a word of caution: this trick will not work for gluten-free baking. If you’re gluten-free, you’re already a wizard dealing with a dozen different powders, and cornstarch alone won’t save you. But for us regular gluten-chompers, this is your get-out-of-jail-free card.

When the Fake Stuff Fails (And It Might)

Let’s be real: your all-purpose swap will never perfectly match super-fine, bleached, commercial cake flour. It’s like using a good karaoke singer instead of Beyoncé—close enough for a Friday night, but not winning any Grammys. Your cake might be slightly denser, or have a slightly less delicate crumb. That’s fine. Nobody is judging you except your Aunt Carol, and she judges everything.

Pro tip: if you’re making a recipe that’s hyper-delicate, like angel food cake or chiffon cake, just buy the real cake flour. Don’t be a hero. Those cakes rely on a paper-thin structure, and your cornstarch blend might betray you with a sad, flat soufflé.

For 90% of cakes—yellow, chocolate, pound, cupcakes—this substitution works like a dream. And if it doesn’t? Blame humidity. Blame your oven. Blame your neighbor’s dog barking at the wrong time. I’ll back you up.

The One Weird Trick That Actually Matters

Here’s the part chefs whisper: measure by weight, not volume. A cup of all-purpose flour can weigh anywhere from 120 to 150 grams depending on how aggressively you scoop it. Cake flour is lighter. So if you’re serious, grab a kitchen scale and weigh out 115 grams of all-purpose flour, then swap 15 grams for cornstarch. That’s your golden ratio. Now you’re a scientist who also eats cake.

But if you’re measuring by cups, just do the two-tablespoon swap and sift like a maniac. I promise, you will survive. Your cake might even taste better because you’ve infused it with smug satisfaction.

Final, Very Unhinged Advice

Look, the entire history of baking is just humans trying to make soft things out of hard flour. You have permission to cheat. The invention of cake flour in the 1930s was a marketing gimmick that worked brilliantly—and now you’ve reverse-engineered it with a box of cornstarch from 2019. You are a culinary outlaw.

Go forth. Bake that cake. Eat it with your hands at 2 a.m. The flour police are not coming for you. And if they do? Tell them I sent you, and that I said sifting three times is the secret to both good cake and a good alibi.