Rainbow Baked Alaska

At least 7 hours or up to 1 week before serving, assemble the sorbet cake: Start with an extra-tall cake ring or round cake pan. We used a stainless-steel cake ring, 5 inches in diameter and 4 inches tall. Place the ring on a rimless baking sheet, and line the bottom and sides of the ring with a double layer of plastic wrap, leaving several inches of overhang. Transfer the ring (still on the baking sheet) to the freezer.

Transfer the sorbets to the refrigerator and let soften for 10 minutes.

Retrieve the cake ring on the baking sheet from the freezer and the strawberry-beet sorbet from the refrigerator. If the sorbet is still firm, transfer to the chilled bowl of a stand mixer fitted with a paddle attachment and beat until malleable but not yet melting, 1–2 minutes. Scoop the sorbet into the ring; using the back of a spoon, spread into an even, smooth layer. Cover with a fresh sheet of plastic wrap; using the bottom of a measuring cup or glass, firmly press the sorbet into the corners of the ring and flatten the surface into an even, smooth layer. Freeze until firm, 15–20 minutes.

Once the first layer is mostly set, retrieve the cake ring on the baking sheet from the freezer and the mango sorbet from the refrigerator. Remove the plastic wrap from the first layer. If the mango sorbet is still firm, transfer to the chilled bowl of a stand mixer fitted with a paddle attachment and beat until malleable but not yet melting, 1–2 minutes. Scoop the mango sorbet onto the first layer; using the back of a spoon, spread into an even, smooth layer. Cover with a fresh sheet of plastic wrap; using the bottom of a measuring cup or glass, firmly press the mango sorbet into the corners of the ring and flatten the surface into an even, smooth layer. Freeze until firm, 15–20 minutes.

Once the second layer is mostly set, retrieve the cake ring on the baking sheet from the freezer and the moringa-soy milk sorbet from the refrigerator. Remove the plastic wrap from the second layer. If the moringa sorbet is still firm, transfer to the chilled bowl of a stand mixer fitted with a paddle attachment and beat until malleable but not yet melting, 1–2 minutes. Scoop the moringa sorbet onto the second layer; using the back of a spoon, spread into an even, smooth layer. Cover with a fresh sheet of plastic wrap; using the bottom of a measuring cup or glass, firmly press the moringa sorbet into the corners of the ring and flatten the surface into an even, smooth layer. Freeze until firm, 15–20 minutes.

Once the third layer is mostly set, retrieve the cake ring on the baking sheet from the freezer and the peach sorbet from the refrigerator. Remove the plastic wrap from the third layer. If the peach sorbet is still firm, transfer to the chilled bowl of a stand mixer fitted with a paddle attachment and beat until malleable but not yet melting, 1–2 minutes. Scoop the peach sorbet onto the third layer; using the back of a spoon, spread into an even, smooth layer. Cover with a fresh sheet of plastic wrap; using the bottom of a measuring cup or glass, firmly press the peach sorbet into the corners of the ring and flatten the surface into an even, smooth layer. Freeze until firm, 15–20 minutes.

Once the fourth layer is mostly set, retrieve the cake ring on the baking sheet from the freezer and the hibiscus-ginger sorbet from the refrigerator. Remove the plastic wrap from the fourth layer. If the hibiscus sorbet is still firm, transfer to the chilled bowl of a stand mixer fitted with a paddle attachment and beat until malleable but not yet melting, 1–2 minutes. Scoop the hibiscus sorbet onto the fourth layer; using the back of a spoon, spread into an even, smooth layer. Cover with a fresh sheet of plastic wrap; using the bottom of a measuring cup or glass, firmly press the hibiscus sorbet into the corners of the ring and flatten the surface into an even, smooth layer. Freeze until the cake is completely firm throughout, at least 3 hours or overnight.

Retrieve the cake from the freezer. Using the plastic wrap around the sides, lift the cake from the ring. (If it sticks, hold under cold running water just until the ring releases.) Remove the plastic wrap and invert the cake onto a small, chilled plate. Transfer to the freezer.

Make the meringue topping: In the bowl of a stand mixer fitted with the whisk attachment, add the egg whites and salt; beat on medium speed until the whites are just frothy, about 30 seconds. With the mixer running, gradually add the sugar, followed by the cream of tartar and the vanilla, then increase the speed to medium-high and continue beating until the meringue holds very glossy, stiff peaks, 5–6 minutes.

Retrieve the cake from the freezer. Using a thin offset spatula, scoop the meringue evenly over the sorbet in decorative swoops and swirls. Freeze for at least 15 minutes and up to overnight.

About 30 minutes before you are ready to serve, transfer the cake to the refrigerator and let soften slightly. Just before serving, use a crème brulée torch to evenly brown the meringue. (If it starts to catch on fire, gently blow out the flame and continue toasting.) To serve, dip a long, heavy knife in warm water and wipe it clean before each cut.