Have egg whites in a large bowl and let stand at room temperature, covered with plastic wrap.Meanwhile combine flour, 3/4 cup.of the granulated sugar, cocoa powder and salt. Sift this mixture trough a sifter or fine mesh strainer into a bowl Set aside

Beat egg whites until soft peaks form, then add cream.of tarter, vanilla and remaining 3/4 cup granulated sugar, adding the sugar in slowly and beat until firm peaks form

Add sifted flour/cocoa mixture to egg whites in 4 additions folding in throughly but gently being careful not to deflate. Use a rubber spatula

Pour into tube pan. Run a metal kitchen knife through batter to remove any air bubbles

Bake 35 to 45 minutes until a long wooden skewer comes out clean

Immediately turn upside down on a,bottle or smooth top.glass,.cool.completely about 1 hour

Run a thin sharp knife along all.walls of pan, including center to release cake.

Melt chopped chocolate and cream in microwave just until chocolate is soft, stir until smooth.Drizzle on cake while warm and liquid.

Melt the white chocolate and cream until soft, stir until smooth. Drizzle on top and around the dark chocolate drizzle add Sparkle sugar and raspberries. Serve with Whipped cream, recipe attached below

https://cookpad.wasmer.app/us/recipes/343417-stabilized-whipped-cream-for-frosting-topping-and-dipping