For the Marshmallow Frosting
Place egg whites, sugar, and cream of tartar in the heatproof bowl of an electric mixer. Set over a saucepan with simmering water. Whisk constantly until sugar is dissolved and whites are warm to the touch, 3 to 4 minutes.

Transfer bowl to electric mixer fitted with the whisk attachment, and beat, starting on low speed, gradually increasing to high, until stiff, glossy peaks form, 5 to 7 minutes. Add vanilla, and mix until combined. Use immediately.

Transfer frosting to a large pastry bag fitted with a large plain round or French tip. Pipe frosting in a spiral motion on each cupcake. Transfer cupcakes to a baking sheet. Using a kitchen torch, lightly brown the frosting, taking care not to burn the cupcake liners. Serve immediately or store in an airtight container, up to 2 days.

For the Whoopie Pies

Preheat oven to 350 F. Place a silicone baking sheet or parchment paper on a cookie sheet.

Once cupcake batter is ready to use, transfer to a piping bag with a medium round tip. Pipe batter into a small circle ~2” in diameter. If making football shaped whoopie pies, pipe into a football shape.

Bake for 8 minutes or until done. Allow to cool on cookie sheet two minutes before removing to a cooling rack.

Pair up the whoopie pies to similar sized and shaped pairs.

Once they have cooled completely, pipe a generous amount of marshmallow frosting onto one of each of the pairs. Toast the marshmallow frosting with a small kitchen torch.

Drizzle with salted caramel sauce. Top with matching whoopie pie pair.