1. Break up the eggs and heat with water.
2. Mix the butter and icing sugar with a spatula, and then beat it with a blender until it becomes fluffy and whitish
3. Add the egg liquid slowly into 4 times, each time you must wait until the egg liquid is fully stirred before adding another amount of egg liquid.
4. Mix the salt and all the powder through a sieve, add to the whipped cream, mix slightly with a spatula, and then mix well with a mixer at a low speed.
5. Add orange zest in one go and stir evenly at low speed
6. Pour the cake batter into a mold that has been spread with non-stick paper, tap it a few times, and use a spatula to smooth the surface until the middle is low and the ends are high.
7. Put it in a preheated oven and bake at 160 degrees for 50 minutes until cooked. (After the surface of the cake is crusted, you can use the tip of a knife to dip it in the middle to make the surface of the cake cracked neatly until it is cooked, or insert a bamboo stick that will not bring out the wet batter to be mature.)
