Preheat your oven to 180°C (350°F). In the bowl of an electric mixer, whisk 12 egg whites and 1 teaspoon cream of tartar on high speed until soft peaks form. Gradually add 1 teaspoon of vanilla extract and 3/4 cup of superfine sugar while whisking, continuing until the mixture becomes thick and glossy. Transfer the egg white mixture to a large bowl.

In a separate bowl, sift together 1 cup of all-purpose flour and the remaining 1/2 cup superfine sugar. Sift this mixture twice more for extra lightness, then sift it over the egg white mixture. Gently fold the dry ingredients into the egg whites until just combined, being careful not to deflate the batter. Spoon the batter into an ungreased angel food cake tin and smooth the top.

Bake the cake for about 30 minutes, or until it begins to come away from the sides of the tin. Immediately invert the cake tin and set it aside to cool for 1 hour. Once cooled, use a butter knife to loosen the cake edges and twist the center funnel to remove. Slice the cake horizontally into 3 even layers using a serrated knife. I always let the cake completely cool upside down in the tin—it helps keep its airy texture!

In an electric mixer, combine the mascarpone, pouring cream, and the remaining 1 teaspoon of vanilla extract. Whisk until stiff peaks form. Place one cake layer on a stand, spread half the raspberry preserves over the layer, then top with half the mascarpone cream. Repeat with another cake layer, the rest of the preserves, and mascarpone cream, finishing with the final cake layer on top.

In a small saucepan, combine 1/3 cup water, 1/2 tsp cream of tartar, and 1 cup superfine sugar. Stir over high heat until the sugar dissolves, then bring to a boil. Reduce the heat and boil for 4 minutes. Meanwhile, whisk 150ml egg whites (about 4 eggs) on high speed in a clean mixer bowl until stiff peaks form. Slowly add the remaining 1 cup superfine sugar, one tablespoon at a time, until thick and glossy. Then, with the mixer running, gradually pour the hot syrup into the egg whites in a thin stream and continue whisking for 4 more minutes until the meringue is shiny and holds stiff peaks. For extra stability, I like to keep whisking until the bowl feels cool to the touch.

Spread the Italian meringue evenly over the assembled cake, covering the top and sides as desired. Serve the cake immediately, or refrigerate for up to two hours before serving for neat slices. To get those beautiful swirls on the meringue, I like using the back of a spoon to create soft peaks all over the cake.