Preheat oven to 375 degrees F.

Butter and flour a 9-inch springform pan set it aside.

In a large mixing bowl whisk together flour, baking powder, salt, ginger, nutmeg, cinnamon, and allspice.

Add the diced butter and work it into the mixture using your fingertips or a pastry cutter, until it resembles fine crumbs.

Using a spatula, stir in 1 cup of sugar.

Slice the apples into very thin pieces, less than ¼-inch thick, then dice those pieces into smaller chunks.

Stir the apples into the flour mixture and toss well to evenly coat all the pieces.

In a separate mixing bowl, whisk together milk, eggs, and vanilla until well combined.

Pour the milk mixture over apple/flour mixture, using your hands or a spatula, toss just until combined (batter will be slightly lumpy, don't over-mix).

Transfer the batter into the prepared baking dish and spread it into an even layer.

In a small bowl stir together the remaining 2 tablespoons of sugar plus ½ teaspoon cinnamon, and sprinkle evenly on top of the cake.

Bake for 45 - 50 minutes, or until a toothpick inserted into the center comes out clean.

Cool for about 5 - 10 minutes on a wire rack then remove the ring from the springform pan and allow the cake to cool completely.

Add the egg yolks and sugar to a medium mixing bowl and beat until pale and fluffy, about 1-2 minutes.

Place a medium saucepan over medium heat and add the milk.

Bring just to a light boil. Reduce burner to medium-low heat, then while whisking egg yolk mixture, slowly pour in ½ cup of the hot milk mixture. Then, while whisking continuously the milk in the saucepan slowly pour the egg yolk mixture into the saucepan.

Cook mixture, whisking constantly, until thickened and it coats the back of a wooden spoon, about 3 - 4 minutes (be careful not to over-heat it, or the eggs will curdle).

Immediately pour into a glass container, and stir in the vanilla extract.

Cover the custard with plastic wrap pressing against the surface to prevent a skin from forming.

Drizzle warm or cold on top of the cake.