You need an 8 inch bowl with a round bottom to make this cake.
1 cup plus 2 tablespoons granulated sugar (divided)
teaspoon cream of tartar
cup cake flour
6 tablespoons cornstarch
3 to 4 tablespoons seedless raspberry jam
1 tablespoon unflavored gelatin (1 packet)
cup cool water
cup granulated sugar
Pinch of salt
cup whole milk
2 teaspoons vanilla
1 cup whipping cream
1 cup fresh or frozen raspberries
Fresh raspberries or raspberry fruit leather for garnish
To make Biscuit Roulade: Preheat oven to 450 degrees. Butter two 13-by-17 inch sheet pans or jellyroll pans, line with parchment paper, then butter and flour paper.
Remove the second cake sheet by gently lifting it out of the pan by the corners of the parchment. Stir raspberry jam until smooth. Spread entire cake with jam all the way to the edges. Don't spread it too thick; you should see the cake through the thin layer of jam.
In a pie pan or other shallow dish. Set aside.
Proceed immediately with assembly.
To assemble: Pour approximately 1/3 of the vanilla cream into the cake-lined bowl; sprinkle with a few raspberries. Continue this process of pouring the cream and adding the berries until all are gone. If any berries are showing, gently press them below the level of the cream, so only white is showing.
If this doesn't work, lay a hot towel over the mold and try again.
Garnish with fresh raspberries.