Line a baking sheet with parchment paper and place the sponge cake layer in the center.

Scoop softened vanilla ice cream onto the cake, shaping it into a smooth dome using an offset spatula.

Freeze the assembled cake and ice cream for at least 8 hours, or overnight, until solid.

Preheat your oven to broil on high. Keep the rack about 6 inches from the heat source.

In a clean, chilled bowl, beat egg whites, cream of tartar, and salt on medium speed until frothy. Gradually add sugar, then vanilla, beating until stiff, glossy peaks form.

Remove the ice cream cake from the freezer and quickly spread meringue all over, sealing the base completely.

Broil for 2–3 minutes, watching closely, until the meringue is evenly golden brown.

Serve immediately, slicing through the crisp meringue, cool ice cream, and soft cake layers for dramatic contrasts.