Lemon Yogurt Sheet Cake with Lemon Curd Swiss Meringue Buttercream

LEMON YOGURT SHEET CAKE

1. Preheat the oven to 350°f /180°c. Grease and line a 9”x13” baking pan with parchment paper, extending the parchment paper over the sides slightly to form a sling.
2. In a large bowl, combine flour, sugar, baking powder, baking soda and salt. Whisk until well combined.
3. In a medium bowl, whisk together the eggs, oil, lemon juice, yogurt and vanilla bean paste. Add the wet ingredients to the dry ingredients, and whisk well to to combine, then switch to a silicone spatula and mix until incorporated.
4. Transfer the mixture to the prepared pan and bake for 40 to 50 minutes, or until a skewer or tester inserted into the middle comes out clean.
5. Allow to cool completely in the pan, then using the parchment paper, transfer to a serving platter.

LEMON CURD

1. Place a medium heatproof bowl over a pot of simmering water, ensuring that the water does not touch the bottom of the bowl. Combine all of the ingredients in the mixing bowl and whisk together.
2. Heat, stirring often, until mixture is thick enough that when you coat the back of a spoon or spatula with curd, you can drag a finger through it, and leave a clear track. Watch the edges of the mixture carefully to ensure that it does not catch and go lumpy, switching to a flexible rubber spatula as needed to help clear the sides of the bowl. Once it is at this point, continue to cook for a further 5 minutes. It will thicken more when it cools. Transfer to a bowl or container, straining through a sieve if you can see any small pieces of egg, then press a piece of plastic wrap directly against the surface of the curd. Place in the fridge to cool completely.

LEMON CURD SWISS MERINGUE BUTTERCREAM

1. Place the egg whites, sugar and salt in the bowl of a stand mixer or a heat proof bowl. Place over a pot of simmering water, ensuring that the water does not touch the bowl. Heat, whisking constantly, until the mixture registers 160˚f (70˚c) on a thermometer and the sugar has dissolved.
2. Carefully transfer the bowl to the mixer, and fit with the whisk attachment. Whip the egg whites on high until they are white and fluffy, 5-6 minutes. Add the butter one chunk at a time, mixing until incorporated (the mixture may look curdled - but just keep mixing, as it will come together). Once all the butter is incorporated, mix on high for a further 3 minutes. Add the vanilla and lemon curd and mix until incorporated.

ASSEMBLY

1. Transfer the buttercream to the top of the cake using a spatula, then evenly spread over the surface of the cake using an offset spatula, creating swoops as desired. Finish with sprinkles as desired.
2. Store leftovers in an airtight container in the fridge.