White Cake in a 9x13 Pan

White cake in a 9×13 pan uses 2 1/4 cups of cake flour, 1 1/2 cups of sugar, 3/4 cup of butter, 1 cup of milk and 5 egg whites, baked at 350°F for 30 to 35 minutes. Using only the whites keeps the crumb pale and soft, and the single sheet is the easiest way to make a white cake for a birthday or a crowd.

Frost it right in the pan with vanilla buttercream and you have about 20 servings with no layering, leveling or crumb coat.

Why a 9×13 Pan Works for White Cake

This batter makes about 5 1/2 cups, which is the same amount you would split between two 9-inch rounds. In a 9×13 it sits just over 1 inch deep and bakes into one even layer about 1 1/2 to 2 inches tall. Egg-white cakes are delicate, and a sheet cake never has to be lifted or stacked, so it is far more forgiving than layers.

Ingredients for a 9×13 White Cake

Cake

2 1/4 cups cake flour (spooned and leveled)
1 1/2 cups granulated sugar
1 tablespoon baking powder
3/4 teaspoon salt
3/4 cup (1 1/2 sticks) unsalted butter, softened
1 cup whole milk, at room temperature
5 large egg whites, at room temperature
2 teaspoons clear or regular vanilla extract
1/2 teaspoon almond extract (optional)

Vanilla Buttercream

1 cup (2 sticks) unsalted butter, softened
4 cups powdered sugar
3 to 4 tablespoons milk or cream
2 teaspoons vanilla extract and a pinch of salt

How to Make White Cake in a 9×13 Pan

Heat the oven to 350°F. Grease a 9×13 pan and line the bottom with parchment.
Combine the dry ingredients. Whisk the cake flour, sugar, baking powder and salt in a large mixing bowl.
Add the butter. Beat the softened butter into the dry mix on low speed until it looks like damp sand, about 1 minute.

Add the liquids. Whisk the milk, egg whites, vanilla and almond extract together. Pour in half and beat on medium for 1 1/2 minutes, then add the rest and beat 30 seconds more, scraping the bowl.
Bake. Spread the batter evenly and bake 30 to 35 minutes, until the top springs back when pressed and a toothpick in the center comes out clean. The top should stay pale, with only the edges turning golden.
Cool completely in the pan, about 1 1/2 hours, before frosting.

Frost. Beat the butter until fluffy, add the powdered sugar a cup at a time, then the milk, vanilla and salt. Spread over the cooled cake.

Cook and Prep Times

Prep: 20 minutes
Bake: 30 to 35 minutes at 350°F
Cool and frost: 1 1/2 hours
Serves: 20 squares

Tips for a Soft, Snow-White Crumb

Use cake flour. If you only have all-purpose, measure 2 1/4 cups, remove 4 1/2 tablespoons and replace them with cornstarch, then sift.
Room-temperature milk and whites keep the batter smooth; cold ones make the butter seize into lumps.

Clear vanilla keeps the cake whiter. Regular vanilla tints it a little ivory but tastes the same.
Do not overbake. A dry white cake almost always spent 5 extra minutes in the oven.

Changing the Pan Size

Two 8- or 9-inch rounds: same batter, bake 25 to 30 minutes.

Two dozen cupcakes: fill liners two-thirds full and bake 18 to 21 minutes.
Half sheet (13×18): make 1 1/2 batches and bake 25 to 30 minutes; the layer is thinner.

Storage

A buttercream-frosted white cake keeps covered at room temperature for 2 days or in the refrigerator for up to 5 days; let it sit out 30 minutes before serving so the frosting softens. The unfrosted sheet freezes for up to 2 months, wrapped well.

Frequently Asked Questions

What can I do with the leftover egg yolks?

Use them in a custard, lemon curd or a batch of homemade ice cream base, cooked until it coats a spoon. Keep them covered in the refrigerator for up to 2 days.

Can I use a box-mix method here?

This recipe is from scratch. If you use a white cake mix in a 9×13 instead, follow the box directions; most bake 28 to 33 minutes.

Why did my white cake sink?

The oven door was opened too early, the baking powder was old, or the batter was overbeaten after the last addition. Check that your baking powder is less than 6 months old.

Looking for another sheet-pan dessert? Try our sopapilla cheesecake in a 9×13 pan.

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White Cake in a 9×13 Pan