6-inch cake
One Purple sweet potato 1 piece (160 grams) Whipping cream 220 milliliters Milk 100 grams Gelatin 2 sheets Sugar 40 grams 1. This is an excellent method for slicing a cake layer. To divide the cake into two layers, choose a plate with a depth equal to half the cake’s height; for three layers, select a plate one-third the cake’s depth. In this case, slicing into two layers, use a plate with a depth half that of the cake, place the cake on the plate, and rest a bread knife against the plate edge while cutting along it. 2. The resulting cake slices are uniform in thickness and smooth. At this point, trim the outer edges of the cake layers slightly.3. First, peel the purple sweet potatoes and steam them until cooked.
4. While still hot, mash the steamed purple sweet potatoes into a paste and set aside. 5. Soak the gelatin sheets in water until softened (this takes only a few minutes). 6. Pour milk into a saucepan, add the softened gelatin sheets and 20 grams of sugar. Cook over low heat until the sugar dissolves, then let it cool (stir continuously while heating). 7. Add the mashed purple sweet potato to the milk mixture and stir until well combined. Set aside. (Here, I used an immersion blender for a smoother texture, as a whisk—which I initially tried—is insufficient.) 8. Prepare a bottle of ice water in the refrigerator in advance. Pour it into a large bowl; due to the hot weather, I also added some ice cubes. 9. Place the heavy cream in a slightly smaller container. 10. Over the ice water, whip the cream until distinct lines form but it remains flowable (this is referred to as whipping over ice water). 11. Pour the whipped cream into the milk mixture and stir evenly to create the mousse filling.12. Wrap a piece of aluminum foil around the bottom of the cake mold to prevent the mousse filling from leaking. Place one cake layer with a slightly trimmed edge into the mold. 13. Pour half of the mousse filling into the mold, covering the cake layer. 14. Place the second cake layer on top, then pour the remaining half of the mousse filling. Refrigerate for about four hours until fully set.
