Preparation Steps

• Preheat oven to 350°F (175°C). Grease and flour a 9-inch round cake pan.
• Make the custard: In a medium saucepan, whisk together 4 eggs, 1 cup sugar, and 3 tablespoons cornstarch until smooth. Gradually whisk in 2 cups of milk. Cook over medium heat, stirring constantly, until the mixture thickens and comes to a boil. Remove from heat and stir in 1 teaspoon vanilla extract. Pour into a bowl, cover with plastic wrap directly on the surface to prevent a skin from forming, and let it cool completely.
• Make the cake batter: In a large bowl, cream together 0.5 cup softened butter and 0.75 cup sugar until light and fluffy. Beat in 2 eggs one at a time. In a separate bowl, whisk together 1.5 cups gluten-free flour, 1 teaspoon baking powder, and 0.5 teaspoon salt.
• Alternately add the dry ingredients and 0.5 cup milk to the butter mixture, beginning and ending with the dry ingredients. Mix until just combined.
• Pour half of the cake batter into the prepared pan. Gently spoon the cooled custard over the batter, spreading it evenly. Top with the remaining cake batter, spreading carefully to cover the custard.
• Bake for 35-45 minutes, or until a toothpick inserted into the cake (avoiding the custard layer) comes out clean. The cake should be golden brown and set.
• Let the cake cool in the pan for 15 minutes before inverting it onto a wire rack to cool completely.