Why Does Cuban Sponge Cake Sink and How to Prevent It from Becoming Dense

The disappointment of a sponge cake rising in the oven only to collapse once it’s out can often be traced back to underbaking or an excess of baking powder. If your cake barely rises and ends up dense, it's worth examining the mixing process and how the flour was incorporated. Observing when the cake lost volume and examining the center after slicing can reveal the issue.

Assessing Air Incorporation When the Cake Barely Rises

For sponge cakes made with beaten eggs, much of the cake’s lightness depends on the air introduced during preparation. King Arthur Baking’s mixing methods distinguish between cakes that start with beating eggs and those that begin by creaming butter and sugar. Each method requires its own procedure, and altering the order can affect the texture.

In Cuban sponge cake recipes using whipped egg whites, these are beaten separately and folded in at the end. There are two critical stages: initially creating volume and then maintaining it. If the egg whites are almost liquid, the initial stage wasn't adequately done; if the mixture is vigorously beaten after adding them, some of the achieved air is lost.

When folding in the egg whites, use gentle, sweeping motions, reaching the bottom of the bowl until no streaks remain. Gentle handling doesn't mean leaving clumps of flour or egg whites. Both preserving air and achieving a smooth mixture must occur simultaneously.

Checking Baking and Avoiding Collapse

A golden surface can mask an unset center. King Arthur explains that removing the cake before its structure is set allows the cake to appear fine briefly before collapsing as it cools. A wet, gummy center requires attention to this aspect.

Near the end of the recommended baking time, check various indicators. A toothpick inserted into the center should come out clean, and the surface should spring back slightly when lightly pressed. If the pan was greased, edges starting to pull away are another clue. Relying solely on the toothpick test can be misleading, so combine these signs.

If your finger leaves a mark or the toothpick comes out with wet batter, continue baking and check again. The suggested baking times serve as guidelines but don't replace observing the center’s condition.

Avoiding Excess Baking Powder

Adding an extra teaspoon of baking powder to ensure the cake rises may have the opposite effect, causing excessive rise followed by a collapse. Measure the specified amount and verify that the product is current and correctly labeled before blaming the oven.

Baking soda and baking powder are not interchangeable in equal amounts. As King Arthur outlines, baking soda requires an acidic component to react, while baking powder already contains both acidic and basic components. Substituting one for the other requires adjusting the recipe. Stick with baking powder if that’s what the recipe calls for, and avoid improvising.

Evaluating Flour and Pan Size

A hard, dry crumb presents a different problem than a wet center. Among the causes of dry cakes, King Arthur highlights excess flour: a heaping or packed cup holds more than when filled without compacting. If the recipe provides grams, using a scale allows for more precise measurement.

Also, use the specified pan. With the same amount of batter, a wider pan creates a thinner layer that cooks faster; maintaining the original time can dry it out. Note the pan's dimensions when a cake turns out well: changing pans alters baking conditions.

Oven Preparation and Cooling

Preheat to the temperature specified by the recipe and avoid frequently opening the door during baking. If your results are consistently off despite following measurements and mixing instructions, an oven thermometer can verify if the actual temperature matches the setting. Don't compensate for a wet center by increasing the heat without first checking the time and pan.

When removing the cake, adhere to the cooling time indicated in the recipe before unmolding. According to CiberCuba’s sponge cake recipe, leaving the cake in the pan for a few minutes, then cooling on a rack, prevents breakage. Unmolding it immediately can cause it to break; allowing it to rest initially helps distinguish between a handling break and a true center collapse.