1. Prepare materials: eggs, sugar, low gluten flour, milk and butter.

2. Whip the egg whites: Separate the eggs and put the whites into a clean container. Use a mixer or whisk to whip the egg whites until stiff peaks appear.

3. Stir the egg yolk batter: In a separate container, whisk the egg yolks and sugar until the sugar is completely dissolved. Then add the milk and melted butter and continue to whisk to combine.

4. Add the flour: Gradually pour the low gluten flour into the egg yolk batter, gently mixing with a cutting motion as you pour. Make sure no flour particles remain.

5. Mix the egg whites and batter: Add the egg whites to the batter in two batches, gently chopping and mixing each time to make the batter smooth and fluffy.

6. Fill the molds: Pour the batter into the prepared cake molds, leaving room for the cake to expand.

7. Bake the cake: Bake the cake in a preheated oven. Generally speaking, the oven temperature is 180-190 degrees Celsius and the baking time is about 25-30 minutes.

8. Verify doneness: Insert a toothpick or bamboo skewer into the center of the cake and if no batter remains when you remove it, the cake is done. If there is still residue, you can continue baking for a while.

9. Cooling Release: Remove the baked cake from the oven and place it on a rack to cool naturally for a while before carefully removing it from the mold.

10. Decorate and enjoy: you can add cream, fruit or chocolate to decorate according to your personal preference, and finally slice the sponge cake to enjoy.

I hope this answer can help you. If there is a bakery related issues can always private message me, to provide you with professional answers. The effect of baking tarts under air conditioning may be affected depending on the specific environment and equipment, so please adjust and try according to the actual situation.