1. Peel the purple sweet potato and cut into small pieces, and steam it in a steamer until it is overripe. Mash the purple sweet potato into a slurry. Use a blender, a rolling pin, or a roller~ Divide the mashed purple potato into two portions, one portion is 60 grams (for cream) and one portion is 100 grams (for cake), and set aside for later use. If you don't make purple sweet potato cream, 100 grams of purple sweet potato is enough. Preheat the oven to 170°C.
2. As shown in the picture~
3. Separate the egg whites and egg yolks, pour 20 grams of granulated sugar and rapeseed oil into a container with egg yolks, and stir thoroughly with a whisk until the liquid is mixed and appears white. The process takes about 3 to 5 minutes.
4. Add 100 grams of purple potato mash.
5. Add 100 grams of purple potato mash.
6. well mixed.
7. 6. Sift in the flour and stir gently.
8. Pour in fresh cream, plain yogurt and purple food coloring (optional, you can also mix red + blue), and stir well with a spatula.
9. Beat the egg whites in another clean container with egg whites.
10. Use an electric whisk to beat the egg white to a foamy twice its original volume.
11. Pour in 20 grams of caster sugar and continue to beat.
12. In the meantime, slowly pour the remaining sugar and starch from the edge of the container. The egg whites are beaten to wet foaming, that is, the egg whites are no longer liquid, but white flowers, firm and shiny, similar to the state of cream. When you lift the whisk, the egg whites can be pulled out with long sharp corners.
13. Mix 1/3 of the whipped egg whites into the purple sweet potato cake batter, and gently evenly lower the density of the two mixtures.
14. Pour in the remaining egg whites, gently and gently with a spatula, while rotating the container, cut and mix evenly from the bottom up. Don't use a whisk! Be patient and mix well slowly. Rough mixing will destroy the beaten egg whites.
15. Pour the cake batter evenly into the cupcake mold, about 2/3, the cake will rise during baking. Gently lift the baking tray and knock it on the table a few times to remove any air bubbles.
16. Bake in the preheated oven for 15 to 18 minutes. Take it out and let it cool slightly before serving. (It doesn't matter if it is split, the most important thing is the deliciousness of home-made.)
17. While the cake is cooling, prepare the cream, add 60 grams of purple potato mash made before to the whipped cream, and mix well.
18. You can apply the purple sweet potato cream directly on the cake, or use a piping bag to squeeze the cream on top of the cake, and then put a few purple sweet potato diced on the cake and you're done! If you want to make it more gorgeous, you can divide the whipped cream into two parts, mix one part with the purple potato mash, one part keep it intact, and then pour half and half into the piping bag, and the squeeze out will be two-color!
Tips:-The baking time can be changed flexibly. A clean bamboo stick can be inserted into the baked cake for inspection. If the bamboo stick is clean after being pulled out, the cake is completely cooked. During baking, the cake mold can be rotated to make the cake heat more evenly.
-If you don't have a steamer, put the purple sweet potato in warm water, put it in the microwave and turn it for 5 to 7 minutes. During this period, the purple sweet potato can be taken out and turned over to ensure even heating.
-Remember to wrap the mashed purple potato with plastic wrap after it is done, otherwise the surface will dry out and form a skin.
-This square cake is made completely on the back of the egg whites, so you must be extra careful when mixing, not rough mixing, otherwise the cake batter will defoam.
-Double the upper part and double the baking time to make a round cake with a diameter of about 18-20 cm (about 6-7 inches in size).
http://www.chayuanshe.com/news/jkys/2015/0522/442.html
