• Preheat the oven to 350 F. Prepare a 9-inch cake pan and line it with parchment paper.

For the Cake

• Squeeze the lemon to get the juice. Divide the juice into 2 small bowls. Peel, core, and then cut the apples into thin slices. One apple should be sliced thinly (for the topping) while the other is diced. An apple slicer would be handy for this. Place each of the apple slices in separate bowls with the lemon juice and toss to coat evenly. Mix in the ground cinnamon with the diced apples. Set aside.
• In a large bowl, combine the flour, baking powder, salt, and ground nutmeg. Add the chilled butter, then use a pastry blender to process/mix until the butter is fully broken up into small pieces (about 1/3 of the size of a pea) and is well coated by the flour mixture. You can also process this briefly in a food processor then transfer to a large mxing bowl.
  
• Pour in the milk, beaten eggs, sugar, and vanilla extract into the flour mixture. Stir until blended and smooth (there are no more big lumps).
  
• Fold in the coarsely chopped apple chunks.
  
• Spoon into the prepared pan.
  
• Arrange the remaining apples on top in an attractive manner. I just form a circle using the Apples but feel free to be creative.
  
• Bake for about 50 minutes or until the cake is done and springs back when lightly pressed. You can insert a toothpick in the center as well, and it’s done when it comes out clean.
  
• Let the cake cool down in the pan for 10 minutes, and then transfer to a wire rack.
• Melt 1 tablespoon of butter. Brush the melted butter mixture all over the cake. Cool completely before cutting. If desired, serve with the custard sauce (optional).
  

For the Vanilla Custard Sauce

• Pour the milk into a saucepan and heat up to medium until bubbles appear along the edges of the pan. In the meantime, whisk together the egg yolks and sugar until thickened and has a lemony color. Slowly pour in the hot milk while stirring. Return the mixture to the saucepan and cook on low heat (not any higher to avoid curdling) until the sauce coats the back of a spoon. Immediately remove from the heat. Strain the sauce in a sieve and then add the vanilla to the sauce. Serve the cake with the warm sauce!!! Drizzle or smother it with sauce; that is your choice!!!