Step 1

Preheat oven to 160 °C (320°F) with the fan on (see note 3 if you don't have a fan function) and line a cupcake tray with cupcake liners.

Step 2

In a bowl, sift together your flour, cornstarch, baking soda, baking powder and salt. Using a whisk or fork, mix until well combined. Set aside.

Step 3

In another bowl, add in your butter, vegetable oil, sugar and lemon zest. Using an electric mixer (hand or stand mixer are both fine - see note 4), cream together for 2 minutes until light and creamy.

Step 4

Add in eggs one by one, mixing well in between each addition (about 10-15 seconds between eggs).

Step 5

Next add in Greek yoghurt and fresh lemon juice. Mix until well combined. The batter may look a little curdled at this stage but that's okay.

Step 6

Lastly add in your premixed dry ingredients from earlier, and using a spatula, gently fold until just combined. Do not overmix. Your batter should no longer be curdled, and there should be no large chunks or streaks of flour. It's okay if the batter is a little lumpy in the end.

Step 7

Distribute the batter evenly into the cupcake liners (fill no more than about 3/4s of the way up), and bake for 18 minutes or until a toothpick comes out clean. Allow to cool in the tray for 10 minutes, before transferring to a wire rack to completely cool. The cupcakes do ever so slightly sink in the middle while cooling , but once you fill and frost them you won't be able to tell. In my opinion, it's a necessary trade-off for the perfect texture :)

Step 8

Add your lemon zest, lemon juice, sugar, cornstarch, milk and vanilla to a saucepan and mix until well combined.

Step 9

Place your saucepan over a medium heat and stir your mixture continuously until you reach a thick consistency (see video for visual).

Step 10

Take your saucepan off the heat and stir in the cold unsalted butter until completely melted.

Step 11

Strain your lemon curd to remove the little bits of lemon zest (optional).

Step 12

Stir in gel colour or turmeric for additional colour (optional). Leave to completely cool.

Step 13

Cream your butter for a few minutes until it's light and fluffy. Either use a hand mixer or stand mixer on a medium high speed. If using a stand mixer, use the paddle attachment.

Step 14

Add in the icing sugar in 3 batches while mixing on low. Ensure that each batch of icing sugar is mixed into the butter well before adding in the next batch.

Step 15

Next add in your cold cream cheese, vanilla and fresh lemon juice. Mix just until the frosting is smooth. Avoid over-mixing (see note 5).

Step 16

Once the cupcakes are completely cool, using the back of a large piping tip (you can also use an apple corer, a small serrated knife or small spoon), and poke it halfway through each cupcake, twist and then bring it back up (see video for demonstration). The middle of the cupcake should come out with the piping tip, leaving a hole in the centre for the lemon curd to go. Remove the part of the cupcake that's in the piping tip (you can use the back of a spoon or toothpick to push it out if it's stuck), and repeat the process with the remaining cupcakes.

Step 17

Next fill the centre of the cupcakes with the lemon curd (see note 6). I just use a teaspoon to do this.

Step 18

Next frost the cupcakes with the cream cheese buttercream. I pop mine into a piping bag with a 1M piping tip on it, and pipe cupcake swirls on the top. Make sure the lemon curd is completely cool before doing this.

Step 19

OPTIONAL: Place any remaining lemon curd in a piping bag, and cut the tip of the piping bag so you have a small hole, and then pipe that in a zig-zag motion on the top of the cupcakes. Enjoy!