- 1 cup plus 2 tablespoons all-purpose flour
- 2 tablespoons cornstarch
- 1 1/4 teaspoons baking powder
- 1/8 teaspoon salt
- 3/4 cup granulated sugar
- 2 large eggs, at room temperature
- 1 1/4 teaspoons pure vanilla extract
- 4 tablespoons unsalted butter, melted
- 1/4 cup vegetable oil
- 1/2 cup milk, at room temperature
- 1 cup granulated sugar
- 3 tablespoons water
- 2 large egg whites, at room temperature
- Pinch of cream of tartar
- Pinch of salt
- Lemon zest
- Lemon juice
- Preheat the oven to 350°. Line a 12-cup muffin tin with paper or foil liners.
- In a medium bowl, whisk the flour with the cornstarch, baking powder and salt.
- In a large bowl, using a handheld electric mixer, beat the sugar with the eggs and vanilla extract at medium-high speed until smooth and thickened slightly, about 3 minutes. Add the butter and oil and beat until incorporated, scraping the bottom and side of the bowl. Add the dry ingredients and milk in 3 alternating batches, beating well between additions. Carefully pour the batter into the lined muffin tins, filling them about two-thirds full.
- Bake the cupcakes in the center of the oven for 20 to 23 minutes, until springy and a toothpick or cake tester inserted in the center comes out clean. Let the cupcakes cool slightly in the muffin tin, then transfer them to a wire rack to cool completely.
- In a small saucepan, combine the granulated sugar with the water and bring to a boil over moderately high heat, stirring constantly until the sugar has dissolved, 2 to 3 minutes.
- In a large bowl of a standing electric mixer, beat the egg whites with the pinches of cream of tartar and salt until soft peaks form.
- With the mixer at medium speed, carefully pour the hot sugar syrup into the egg whites. Continue beating the frosting until cool and billowy, about 5 minutes. Mix the frosting with the lemon zest and juice to taste.
- Preheat the broiler. Spread the frosting on the cooled cupcakes. Transfer the cupcakes to a baking sheet and broil for 30 seconds, or until the frosting is toasted; serve.
The unfrosted cupcakes can be wrapped in plastic and stored at room temperature for up to 2 days or frozen for up to 1 month.