1. Preheat the oven to 175℃. A 9-inch diameter cake baking pan with detachable outer ring and bottom, oiled, thinly sprinkled with flour, and patted off the excess flour. 2. Add softened pure butter and fine sugar into a large container and beat well with an egg beater. Add eggs, one at a time, and stir at medium speed for one minute after each addition. Add vanilla extract and stir well. 3. Mix the flour, baking powder and lemon peel, add them to the oil and sugar egg paste mentioned in the previous paragraph, and stir evenly with chopsticks or a plastic knife. Pour it into the greased baking box. 4. Put the apples face down and arrange them evenly on the batter surface. Sprinkle with coarse sugar and almond slices. Bake in a preheated oven for 50-60 minutes, or insert a toothpick or bamboo stick in the center of the cake, if it doesn't stick to the wet paste. 5. Take it out of the oven, cool it for 10 minute, draw a circle around the baking box with a knife, remove the outer circle of the baking box, keep the bottom, and put it on the iron frame for cooling.