- Place a rack in the center of the oven and preheat to 375 °F.
- Grease and flour a 9-inch spring-form pan.
- In a large bowl, add salt, butter, 2 cups flour, and ½ cup sugar.
- Cut in butter with your fingers or with a pastry blender until crumbly.
- Remove 1 cup of the crumbs and press them over the bottom and about ½ inch up the sides of the spring-form pan, making a crust about ⅛ inch thick.
- Make a well in the remaining crumb mixture.
- Add the milk, eggs, vanilla, lemon zest, the remaining 3 tbsp flour, and the baking powder.
- With a whisk, blend this mixture thoroughly, without incorporating the crumbs.
- Then, with a wooden spoon stir in the crumbs until well blended but still a little lumpy.
- Core, peel and chop apples into ½ inch pieces, then fold the apples into the mixture.
- Scrape the batter into the pan.
- In a small bowl, beat the egg white until foamy.
- Beat in the remaining 2 tbsp sugar and beat until the whites barely stand in peaks.
- Spread over the top of the batter.
- Bake 65 – 75 minutes or until a knife inserted in the center comes out clean.
- Remove from the oven and cool 30 minutes on a wire rack.
- Slip off the sides of the pan and finish cooling the cake.
- Serve at room temperature.
- Covered in plastic wrap, the cake holds well at cool room temperature up to 2 days. It keeps a week in the refrigerator. Either way, warming it in the oven makes it even tastier.
- Easy to move around and heat if you leave it on the pan base (when cold, put in a cold oven on a tray, set temperature to 350 °F. Turn off oven when temperature reaches 350 °F).
- Delicious served alone, but one could add whipped cream.