Creating the Lemon Yogurt Sheet Cake with Lemon Curd Swiss Meringue can be a fun and straightforward process if you follow these steps:

1. Preheat the Oven: Preheat your oven to 350°F (175°C). Grease and flour a 9×13-inch baking dish to prepare it for the batter.

2. Mix Dry Ingredients: In a large mixing bowl, whisk together the flour, baking powder, and salt until combined. Set aside.

3. Combine Wet Ingredients: In another bowl, whisk the yogurt, sugar, vegetable oil, eggs, lemon zest, and lemon juice until smooth.

4. Combine Mixtures: Gradually add the wet ingredients to the dry ingredients, stirring until just combined. Be careful not to over-mix; a few lumps are okay.

5. Bake the Cake: Pour the batter into the prepared baking dish. Bake for 30-35 minutes or until a toothpick comes out clean from the center. Allow the cake to cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.

6. Make the Lemon Curd: In a saucepan, whisk together eggs, sugar, lemon zest, and lemon juice. Cook over low heat, gently stirring until thickened. Remove from heat and add butter, stirring until melted and smooth. Transfer to a bowl and let cool.

7. Prepare the Swiss Meringue: In a heat-safe bowl, combine egg whites and sugar. With a mixer, beat over simmering water until sugar is dissolved and the mixture is warm to the touch. Remove from heat and beat until glossy peaks form, then add vanilla extract.

8. Assemble the Cake: Once the cake has cooled completely, spread a generous layer of lemon curd over the top. Pipe or spread the Swiss meringue on top of the lemon curd, creating swirls for added texture.

9. Brown the Meringue (Optional): Use a kitchen torch to toast the meringue lightly, or place it under the broiler for a few minutes, watching carefully to avoid burning.

10. Serve and Enjoy: Allow the cake to set for at least 30 minutes before slicing. Dust with powdered sugar before serving if desired.