1. Add the egg yolks to the oil, milk, and sugar and mix until the oil and water are mixed.
2. Sift in the flour and mix until there are no particles.
3. Put the egg whites in a clean, water-free and oil-free container, add sugar and vinegar and beat until stiff foaming.
4. Add 1/3 egg white paste and egg yolk paste and mix well.
5. Pour the remaining 2/3 egg white paste and stir well.
6. Pour it into a baking pan covered with greased paper, smooth it out, shake it lightly, and shake out big bubbles. (My baking tray is 37cm*28cm.)
7. Put it in a preheated 350F/180C oven and bake for 20 minutes, take out the topside and place it on the grilling net, tear off the greased paper while it is hot, and let it cool. (The oil paper should be covered on the cake to prevent the cake from being too dry.).
8. Buckle the cake back on the greased paper.
9. Spread milky syrup (mayonnaise) and sprinkle with pork floss.
10. Roll up the cake, seal on both sides, put it in the refrigerator for 15-20 minutes to shape, and then slice it for consumption.
11. The cake is soft, salty and sweet, and it is a good match.
