Peel and cut purple sweet potato into small pieces. Steam on high heat for 10 minutes or until soft.
Mashed the purple sweet potato used to make the cake, and let the rest cool for later use.
Put baking paper on the bottom of the mold.
Add enough water to the steamer to preheat.
Put the egg yolk in the mashed purple sweet potato, then add corn oil, salt, and milk, and then mix well.
Put the egg whites into a large bowl free of oil and water, and add lemon juice or white vinegar.
After beating with a whisk at high speed until the egg whites appear coarse foam. Add fine sugar in 3 portions, and continue to beat at high speed until stiff peak.
Pour in the purple sweet potato paste and continue to stir evenly with a whisk.
Sift in the cake flour in 3 portions, and mix until there is no dry powder with the folding method.
Pour the batter into the mold, use chopsticks to eliminate bubbles, and smooth the batter.
Put it in a preheated steamer and steam for 55 minutes on medium-low heat (Leave a seam on the lid), then turn off the heat and leave for 5 minutes.
Press lightly along the edge of the mold after it is out of the pot, and place it on the cooling rack to cool for at least one hour after demolding.
After the cake base has cooled and stabilized, slice it into 3 or 4 slices for later use.
Jelly Layer And Final Jelly Cake
Pour purple sweet potato, corn starch, coconut milk, and water into a blender and beat until smooth and set aside.
Boil a pot of hot water for later use. This is used to keep the jelly paste warm later.
Mix the sugar and konnyaku powder evenly and then pour it into the dry pan.
Add water and stir until there are no lumps before turning on the fire.
Stir on low heat until the water boils, then slowly pour in the purple sweet potato paste, stirring while pouring. Stir until it boils and then turn off the heat. Then keep warm the cooked jelly with hot water, which can slow down the solidification speed of the jelly.
Scoop 3 scoops of batter into the cake mold to spread it evenly.
Put in a piece of cake and press gently. Scoop 2 to 3 spoons of jelly and spread it evenly. Repeat until the cake is finished.
Let it cool for 10 minutes, then wrap it in plastic wrap and put it in the refrigerator for at least 2 hours.
Press lightly along the edge of the mold, and then shake the mold upside down to release the mold. Cut it into the size you like.