Key Lime Cupcakes

Directions

1. 1
   Preheat oven to 325°F. Line a standard muffin tin with paper liners. Whisk together flour and salt.
2. 2
   In a small bowl mix together graham cracker crumbs, 2 tablespoons of sugar, and butter. Set aside.
3. 3
   With an electric mixer on medium-high speed, cream butter and 2/3 cup sugar until pale and fluffy, scraping down sides of bowl every few minutes. Add lime zest. Reduce speed to medium, and add vanilla. Add eggs, one at a time, beating until until incorporated, scraping down sides of bowl as needed. Reduce speed to low. Add flour mixture in four batches, beating until completely incorporated after each.
4. 4
   Place 1 tablespoon graham cracker mixture into the bottom of each prepared muffin cup. Use the bottom of a small glass to pack crumbs into the bottom of each cupcake liner. Reserve remaining graham cracker mixture for topping.
5. 5
   Transfer muffin tins to oven and bake until the edges of the graham cracker mixture is golden, about 8 minutes. Remove from oven and fill each muffin cup three-quarters full with cake batter; tap pan on counter-top once to distribute batter. Sprinkle each with remaining graham cracker mixture trying to avoid sprinkling over the center of each muffin as they will scooped out.
6. 6
   Bake, rotating tin halfway through, until a cake tester inserted in centers comes out clean, about 20 minutes. Transfer tin to wire racks to cool 10 minutes; turn out cupcakes onto racks and let cool completely. Cupcakes can be stored up to 2 days refrigerator, in an airtight container.
7. 7
   ?To assemble the cupcakes, use a paring knife to cut out a cone shape out of the center of each cupcake the size of a quarter.
8. 8
   ?Remove chilled lime curd from the refrigerator and stir to loosen. Place curd in a squeeze bottle or pipping bag to ease filling the center of each cupcake. Fill each cupcake just to the top.
9. 9
   Transfer frosting to a large pastry bag fitted with a large French tip (such as Ateco #844). Pipe frosting in a spiral motion on each cupcake, just large enough to cover the lime curd without covering the surface of the entire 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 refrigerated in an airtight container, up to 2 days.
10. 10
    Place sugar and lime zest in a mortar and grind with a pestle to combine and release the oils. Transfer sugar mixture to a medium heatproof bowl along with eggs and egg yolks; whisk to combine. Place over a saucepan of simmering water and whisk until sugar has dissolved. Add lemon juice and continue whisking until mixture is thick and reaches 160°F on an instant-read thermometer, scraping down sides of bowl as necessary. Add butter and whisk until well combined.
11. 11
    Pour lime curd into a clean medium bowl. Cover lime curd with plastic wrap, pressing plastic wrap directly onto surface. Transfer to refrigerator until completely chilled.
12. 12
    Marshmallow Topping: 2 large egg whites 1/2 cup sugar 1/4 teaspoon cream of tartar
13. 13
    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.
14. 14
    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.