Gluten-Free Vanilla Layer Cake

Before you start

Gluten-free cake can be just as soft as a wheat cake because cake was never meant to be chewy in the first place. What gluten-free blends need is hydration and structure: rice and starch flours absorb liquid slowly, so a short rest before baking takes away the sandy texture, and xanthan gum stands in for the gluten that would normally hold the bubbles.

Use a measure-for-measure blend that already contains xanthan gum, and weigh it. Blends range from about 125 to 155 grams per cup depending on the brand, so cup measurements are unreliable here. Sour cream adds moisture and fat, which keeps the crumb from drying out by the second day.

Ingredients

• Cake300 g gluten-free 1:1 baking flour blend with xanthan gum — about 2¼ to 2½ cups depending on brand
• 2½ tsp baking powder — labeled gluten-free
• ½ tsp baking soda
• ¾ tsp fine salt
• 170 g (¾ cup) unsalted butter — softened
• 300 g (1½ cups) granulated sugar
• 3 large eggs — room temperature
• 1 large egg yolk
• 1 tbsp pure vanilla extract
• 120 g (½ cup) full-fat sour cream — room temperature
• 120 ml (½ cup) whole milk — room temperature
• Frosting225 g (1 cup) unsalted butter — softened
• 375 g (3 cups) powdered sugar — sifted
• 2 to 3 tbsp whole milk or cream
• 2 tsp vanilla extract or vanilla bean paste
• 1 pinch fine salt

Method

1. Grease the pans and line the bottoms with parchment. Do not dust them with wheat flour; use a little of the blend or skip the dusting.
2. Whisk the flour blend, baking powder, baking soda and salt. Sift if the blend looks lumpy, since starch clumps do not break up in the batter.
3. Beat the butter and sugar on medium-high for 4 to 5 minutes, until pale and fluffy. The extra creaming adds lift that the gluten-free flour cannot give on its own.
4. Beat in the eggs and yolk one at a time, then the vanilla. Whisk the sour cream and milk together until smooth.
5. On low speed, add the dry ingredients in three parts alternating with the sour cream mixture in two. Once everything is in, beat on medium for 30 seconds; unlike wheat batter, this one does not toughen with mixing and the short beat helps structure.
6. Divide the batter between the pans and let it rest at room temperature for 20 minutes. Meanwhile heat the oven to 175°C (350°F) with a rack in the center.
7. Bake for 28 to 32 minutes, until golden at the edges, springy in the center and a toothpick comes out clean. Gluten-free cakes can look done before they are set, so trust the toothpick.
8. Cool in the pans for 15 minutes, then turn out onto a rack and cool completely, about 1 hour. The layers are fragile while warm.
9. Beat the frosting butter for 3 minutes, add the powdered sugar and salt on low, then the vanilla and enough milk to make it smooth and spreadable. Fill and frost the cake.

Tips for success

• If your blend has no xanthan gum, add ¾ tsp to the dry ingredients. Too much gum makes the crumb springy and slightly rubbery.
• Cool the layers fully, or chill them for 30 minutes before frosting. Cold gluten-free layers are much less likely to crack when you move them.
• Wrap any cut layers tightly. Gluten-free crumb stales faster than wheat crumb once exposed to air.

Substitutions

Sour cream

Full-fat plain Greek yogurt works with a slightly tangier result. Low-fat versions give a drier cake.

Butter (dairy-free)

Use plant-based baking sticks in both cake and frosting, and replace the milk and sour cream with unsweetened oat milk and dairy-free yogurt. Expect a softer frosting that needs more chilling.

1:1 flour blend

Different blends behave differently. Rice-heavy blends can taste gritty and benefit from the full rest; blends with more starch bake lighter but more fragile. Stick with one brand once you like it.

Variations

Gluten-free cupcakes

Fill 24 lined muffin cups two-thirds full and bake for 18 to 21 minutes. Frost with half the buttercream or the full batch for tall swirls.

Almond vanilla cake

Replace 50 g of the flour blend with almond flour and add ½ tsp almond extract. The crumb becomes moister and slightly denser.

Troubleshooting

Gritty or sandy texture

The flour did not have time to hydrate. Rest the batter 20 to 30 minutes before baking, and choose a finely milled blend.

Cake sank in the middle after cooling

It was underbaked or had too much leavening. Bake until a toothpick is clean, measure baking powder with a level spoon, and avoid opening the oven in the first 20 minutes.

Crumbly layers that break when stacked

The blend may lack enough binder. Check for xanthan gum, add the extra yolk as written, and chill the layers before assembling.

Gummy streak at the base

Batter sat too long in a warm kitchen or the oven was too cool. Keep the rest to 30 minutes at most and check your oven with a thermometer.

Storage

Store the frosted cake covered at cool room temperature for up to 2 days, or refrigerate it for up to 4 days and bring slices to room temperature before eating. Unfrosted layers freeze well for up to 2 months if wrapped tightly.

Safety notes

For anyone with celiac disease, check that every ingredient, including baking powder, vanilla and powdered sugar, is labeled gluten-free, and clean pans, bowls and sieves that have touched wheat flour. Contains egg and milk. Do not taste the raw batter.