1. Take out one egg yolk and put it in a piping bag for later use. Sift the low-gluten flour and set aside.
2. Put a whole egg and four egg yolks into a bowl for later use, and put the remaining one egg white and the other four egg whites into a water- and oil-free basin.
3. Put the butter in a pot and simmer until it boils.
4. Turn off the heat and add the sifted low-gluten flour, mix well.
5. Add warm milk and mix well.
6. Add the whole egg and egg yolk to the batter in batches, and mix well each time before adding to the next. Finally add rum and mix well.
7. Preheat the oven to 180 degrees, add a few drops of egg whites and lemon juice in three times, add fine sugar and beat until a neutral foaming state.
8. Take one third of the egg white paste and add it to the egg yolk paste, cut and mix evenly.
9. Pour into the remaining egg white batter, cut and mix evenly, the cake batter after mixing is smooth and shiny.
10. Pour it into a baking tray lined with greased paper and shake out large bubbles.
11. Cut a small opening in the piping bag with the egg yolk, squeeze out the parallel line diagonally from left to right, use a chopstick, perpendicular to the parallel line, draw one line from the top left to the bottom right, and then draw one line from the bottom right to the top left, in sequence Continue to draw to both sides, with the two adjacent lines in opposite directions. Put it in the preheated oven at 180 degrees for 25 minutes.
12. After baking, take out the cake, dry to lukewarm, cut into pieces and enjoy.
13. Finished product
