An Archival Lemon-Soda Sponge Cake Recipe

I have used this recipe for many years and wanted to share it. I find it very simple, and the original says it can be made without a mixer or multicooker.

Ingredients

• 4 eggs
• 1½–2 cups sugar
• 1 packet vanilla sugar (packet weight unspecified in the source)
• 1 cup carbonated lemon soda, or another carbonated soft drink
• 1 cup vegetable oil, preferably refined
• 3 cups flour
• 10 g baking powder

Editor’s note: The source does not specify the cup volume, vanilla-sugar packet weight, or pan size. Because cup measures are mixed with fixed egg and baking-powder amounts, exact proportions and baking time cannot be guaranteed. Treat this as an archival recipe. The source also says baking soda can replace baking powder but gives no amount; do not substitute it 1:1. Keep the 10 g baking powder unless using a separately tested conversion suitable for the drink’s acidity.

Mix the batter

Beat the eggs with the vanilla sugar and sugar. Add the oil, mix, and immediately add the carbonated lemon soda. Add the flour in batches, mixing the baking powder into one batch first. The batter should have a consistency similar to sour cream.

Bake

Line a deep-sided baking pan—the cake rises considerably—with parchment, and grease the parchment if desired. The source gives a broad range of 180–200°C (356–392°F). Start at 180°C unless a tested oven-and-pan combination requires otherwise. Bake for about 30 minutes, then check the center with a wooden skewer; it should come out without wet batter.

Once the cake is baked, the source recommends turning off the oven and leaving it there to rest and cool for 20–30 minutes. Residual heat varies, so remove the cake sooner if it continues to brown or dry.

Do not taste raw batter: raw flour and eggs can contain harmful bacteria. Wash hands, bowls, utensils, and work surfaces after handling them, and use oven mitts for the hot pan.

Dust the finished sponge cake with powdered sugar, or slice it into layers for a cake.

Enjoy it with tea!