Prep those apples

Start by peeling, coring, and slicing your apples into ⅛-inch slices. Microwave them in a shallow dish in one-minute intervals, stirring in between, until they’re soft and pliable (about three minutes total). Once softened, toss them with a teaspoon of lemon juice to keep their color vibrant and fresh. Let them cool completely—this step ensures they won’t steam and make your cake soggy.

Make the batter

In a medium bowl, whisk together 1 cup of flour, 1 cup of sugar, baking powder, and salt. In a separate large bowl, mix the whole egg, milk, oil, and vanilla bean paste until smooth. Gradually combine the dry ingredients with the wet ones, stirring gently until just moistened. (Pro tip: Overmixing will make the cake dense, so keep it light.) Set aside 1 cup of this batter for later—it’s going to create that pretty, golden topping.

Layer it up

Add the remaining two egg yolks to the larger portion of batter and whisk until smooth. Fold in your cooled apple slices, making sure every piece is evenly coated. Pour the apple mixture into your buttered and lined springform pan, pressing the apples gently into an even layer. To the reserved batter, whisk in the remaining two tablespoons of flour and spread it evenly over the apples. A sprinkle of sugar on top adds a delicate crunch when baked.

Bake to perfection

Bake at 325°F for 1 hour to 1 hour 15 minutes. You’ll know it’s done when the top is golden brown and a toothpick inserted into the center comes out clean. Let the cake cool completely on a wire rack before removing it from the pan. This step is key—trust me, the cake is delicate while warm and needs time to set.

Whip up the custard sauce

While the cake cools, make the maple ginger custard sauce. Combine milk, maple syrup, and ginger slices in a saucepan and bring it to a gentle simmer. Turn off the heat and let the ginger steep for 30 minutes. Strain out the ginger, reheat the milk mixture, and temper the egg yolks by adding a small amount of warm milk while whisking. Combine everything back in the saucepan and cook, stirring constantly, until the custard thickens and coats the back of a spoon. Stir in vanilla bean paste, then cool completely before refrigerating.