Lemon Sponge Cake with Mint and Lemon Syrup
A lean 8-inch sponge risen on whipped egg whites and oil rather than butter, with mint rubbed into the sugar so it perfumes the crumb. Soaked warm with a mint-steeped lemon syrup, which is what keeps it moist for three days.
Ingredients
The Mint Sponge
- 1 tablespoon softened butter for the pan, plus flour for dusting
- 1/3 cup packed fresh spearmint leaves about 1/2 ounce, plus sprigs to serve
- 3/4 cup granulated sugar divided
- 4 large eggs separated, at room temperature
- 1/3 cup mild olive oil or vegetable oil
- 1/4 cup whole milk at room temperature
- 3 tablespoons lemon juice
- 1 tablespoon finely grated lemon zest from about 2 lemons
- 1 teaspoon baking powder
- 1 cup all-purpose flour plus 2 tablespoons, spooned and leveled
- 1/4 teaspoon fine sea salt
- 1/4 teaspoon cream of tartar
The Mint Lemon Syrup
- 1/2 cup granulated sugar
- 1/3 cup water
- 6 sprigs fresh mint steeped off the heat
- 1/3 cup lemon juice
- 2 teaspoons finely grated lemon zest
Equipment
- 8-inch round cake pan
- Electric mixer
- Mixing bowls
- Rubber spatula
- Saucepan
Instructions
Prepare the Pan and the Mint
- Heat the oven to 350F. Butter an 8-inch round cake pan, line the base with parchment and dust the sides with flour.
- Rub the mint leaves into 1/4 cup of the sugar with your fingertips until the sugar is damp, tinted green and strongly fragrant, about a minute. Chop the spent leaves finely and keep them with the sugar.
Make the Yolk Batter
- Whisk the egg yolks with the mint sugar and another 1/4 cup of the sugar until pale and thick, then whisk in the oil, milk, lemon juice and zest.
- Sift the flour, baking powder and salt over the top and fold just until no dry flour is visible. Do not beat it smooth.
Whip and Fold
- Beat the egg whites with the cream of tartar to soft peaks in a scrupulously clean bowl, then add the last 1/4 cup of sugar in a steady stream and beat to a glossy medium peak that curls over at the tip.
- Stir a third of the whites into the yolk batter to loosen it, then fold in the remainder in two additions with a large spatula, stopping the moment no streaks remain.
Bake
- Spread the batter into the pan, level the top and bake 35 to 40 minutes, until the top is domed and crackled, the edges have pulled in slightly and the center reads 205F to 210F. Cool in the pan for 15 minutes.
Make the Syrup and Soak
- Combine the sugar, water and lemon juice in a small saucepan over medium heat, bring to a boil and simmer 3 minutes. Take it off the heat, add the mint sprigs and the zest, steep 10 minutes, then lift the sprigs out and let the syrup cool to barely warm.
- Poke the still-warm cake right through to the base 40 or 50 times with a thin skewer, then spoon over half the syrup in three passes, letting each soak in. Rest at least 1 hour before slicing and pass the remaining syrup at the table.
Notes
Rub the mint into the sugar with your fingers until the sugar is damp, green and strongly fragrant. This is where most of the mint flavor comes from; chopped leaves alone bake brown and taste of little.
Eggs must be at room temperature. Cold whites whip to roughly half the volume.
Beat the whites to a glossy medium peak that curls at the tip, not to stiff dry peaks. A dry foam tears rather than folds and you lose more air stirring the lumps out.
Spearmint, not peppermint. Peppermint carries far more menthol and tastes medicinal here.
Doneness is 205F to 210F in the center. A skewer can read clean while the middle is still setting, and an underbaked sponge sinks as it cools.
Soak a cake that has cooled about 15 minutes with syrup that is barely warm. Both hot and the syrup runs straight through; both cold and nothing absorbs.
Rest an hour before slicing so the syrup redistributes.
Storage: 3 days covered at room temperature. Freeze unsoaked only.
Nutrition values are an estimate.
Inspired by a Giada De Laurentiis lemon-mint cake.
Nutrition
Serving: 1slice | Calories: 304kcal | Carbohydrates: 45g | Protein: 5g | Fat: 12g | Saturated Fat: 2g | Polyunsaturated Fat: 2g | Monounsaturated Fat: 8g | Cholesterol: 93mg | Sodium: 136mg | Potassium: 88mg | Fiber: 1g | Sugar: 30g | Vitamin A: 180IU | Vitamin C: 8mg | Calcium: 42mg | Iron: 1mg