1. Take a large bowl, add flour, sugar, baking powder, salt, and gelatin powder and mix well.
2. Dig a hole in the middle of the flour mixture and add the oil, egg yolk, and water in order.
3. Take another bowl, add egg whites and tartar powder.
4. Use an electric whisk to beat the egg whites at high speed until you can pick up a corner.
5. Stir the flour mixture well.
6. Pour the egg whites in three times, and stir gently after each pour.
7. Pour the batter into a six-inch baking pan. My cake mold has a live bottom, so it is covered with a layer of tin foil.
8. Preheat the oven to 160 degrees and bake for about 40 to 45 minutes. After roasting, buckle upside down and let it cool off the mold.
