Preheat the oven to 350 degrees F (180 degrees C). Add cupcake liners to a muffin pan.

In the bowl of a stand mixer fitted with the paddle attachment, combine the flour, sugar, baking powder, and salt.

Cut up the butter into small cubes and add to the dry ingredients. Mix on low speed until it resembles wet sand.

Add the oil, yogurt, milk, and vanilla, and mix until just combined.

In a separate bowl, whip the egg whites to stiff peaks. Gently fold it into the batter with a rubber spatula until just combined.

Fill the cupcake liners about ⅔ of the way full.

Bake for 16-18 minutes or until a toothpick inserted comes out clean.

Cool completely before decorating.

In a medium bowl, whisk together the sugar, cornstarch, and salt until no lumps remain.

In a medium saucepan over low-medium heat, melt the butter.

Whisk in the sugar mixture, then the lemon juice and egg yolks until fully combined, about 1 minute.

Use a rubber spatula to constantly stir the mixture for another 2-3 minutes or until large bubbles form in the center. Immediately remove from heat.

Strain the lemon curd into a bowl. Press plastic wrap up against the surface to prevent a skin from forming, and chill for at least 2 hours or overnight.

In a double boiler, heat the egg whites, sugar, and salt, whisking frequently until it reaches 160 degrees F or until the sugar is completely dissolved and the egg whites do not feel grainy.

Transfer the bowl to the stand mixer with a whisk attachment. Whisk on high speed until soft peaks form, then add the vanilla.

Continue mixing until stiff peaks form.

Decorate the cupcakes immediately.

With a small (about ½") round cookie cutter, remove the centers of the cupcakes, pressing about ⅔ of the way into them.

Cut the very top of the centers off and reserve them.

Fill the cupcakes with lemon curd and place the top of the centers back on.

Pipe the meringue as desired and use a kitchen torch to give them a toasted look. Enjoy!