01 - Line an 8-inch bowl with plastic wrap, leaving overhang. Pack softened ice cream into the bowl and smooth the surface. Cover and freeze until completely firm, at least 4 hours or overnight.
02 - Place the sponge cake layer on a parchment-lined baking sheet. Unmold the ice cream dome onto the cake base by lifting the plastic wrap, then refreeze while preparing the meringue.
03 - In a clean, dry bowl, beat egg whites with cream of tartar until soft peaks form. Gradually add granulated sugar while continuing to beat until stiff, glossy peaks develop. Incorporate vanilla extract.
04 - Preheat the oven to 450°F or ready a kitchen torch for toasting the meringue.
05 - Quickly spread the meringue evenly over the ice cream and cake, sealing all edges and covering completely. Create decorative swirls with a spatula.
06 - Bake in the preheated oven for 3 to 5 minutes until the meringue is golden brown, or toast using a kitchen torch.
07 - Slice and serve immediately to maintain texture contrast.