For 8.5-inch form:
Making the Biscuit:
- Add sugar, salt, and vanilla extract to the room-temperature eggs and whip until they increase in volume and lighten in color.
- Bring the milk and butter to a boil.
- Sift the flour and gradually add it to the egg mixture, mixing gently by hand.
- Slowly add the hot milk and butter mixture, continuing to mix by hand.
- Lightly grease the mold with oil.
- Bake in the oven at 360°F (180°C) for 20 minutes in an 8.5-inch form.
- Let the biscuit cool, then cut off the top.
- Place the biscuit into an 8-inch round form and line the sides with wax paper.
- Lightly grease the wax paper with a little oil.
- Soak the biscuit with a small amount of smoothie.
Making the Orange Mousse:
- Squeeze enough oranges to get 800 ml of orange juice.
- Mix 500 ml of the juice with 120 g of sugar and heat gently (do not boil) until the sugar dissolves.
- Set aside 100 ml of the juice for soaking the sponge layer.
- Soak 18 g of gelatin in 70 ml of juice, then warm it over a water bath until fully dissolved.
- Gradually stir the warm gelatin into the sweetened orange juice.
- Tip: Chill the mixing bowl and whisk attachment in the refrigerator beforehand.
- Whip the cold heavy cream until soft peaks form (about 4–5 minutes on medium speed), adding powdered sugar after 2 minutes of whipping.
- Gently fold the whipped cream into the orange juice and gelatin mixture, stirring constantly.
- Soak the sponge with the chilled sweetened juice.
- Pour the mousse mixture over the biscuit layer in the form.
- Refrigerate for 1 hour to set.
Preparing the Orange Jelly:
- Add 85 g of sugar to 300 ml of orange juice and heat until the sugar dissolves (do not boil).
- Soak 7 g of gelatin in a small amount of juice and warm it over a water bath until dissolved.
- Gradually stir the warm gelatin into the sweetened orange juice.
- Pour the cooled jelly mixture over the mousse layer in the form.
- Refrigerate for 3–4 hours until fully set.
- After refrigerating the cake, carefully remove it from the form.
- Decorate as desired.
- I used grated white chocolate, fresh fruit, and mint leaves.
Note: I used an 8.5-inch pan for baking and an 8-inch pan for assembling the cake so the sponge fits tightly in the form. You can also use a larger baking pan and then trim the edges to fit the 8-inch cake form.