Soft vanilla bean cake layered with homemade raspberry syrup and raspberry buttercream. The perfect small batch birthday cake. No leftovers, just enough cake.
Preheat oven to 350°F and prepare a 6-inch cake pan. Whisk together the all-purpose flour, cornstarch, baking powder, and 1/2 teaspoon salt. In a separate bowl, beat the 4 tablespoons of unsalted butter, vegetable oil, and 3/4 cup granulated sugar until light and fluffy. Mix in 2 teaspoons vanilla extract, eggs, and whole milk. Gradually fold the dry ingredients into the wet ingredients until just combined. Pour the batter into the prepared cake pan. Bake for 45–50 minutes, tenting with foil if the top browns too quickly. Cool completely in the pan before removing.
For the Raspberry Syrup: In a small saucepan, combine 1 cup fresh raspberries and 2 tablespoons granulated sugar. Cook over medium heat for 8–10 minutes, stirring occasionally, until the raspberries break down and the mixture thickens slightly. Strain the syrup through a fine-mesh sieve to remove seeds, then cool completely.
For the Buttercream: In a large bowl, beat 1/2 cup unsalted butter until creamy. Gradually mix in 2 1/2 cups powdered sugar, 1 tablespoon vanilla extract, and 1/2 teaspoon salt. Add 1–2 tablespoons heavy cream and 2–3 tablespoons of the cooled raspberry syrup, beating until the buttercream is smooth and fluffy.
To Assemble: Once the cake is completely cooled, frost it with the raspberry buttercream. Decorate with fresh raspberries if desired.
