Showstopper Tiramisu Cake

Sponge cake

1. Read through the full recipe, including tips below before starting. Trust us on this one.
2. Preheat your oven to 180° C/350° F and line the base of the two 8” cake tins with parchment paper.
3. Combine 100g of plain flour and 25g of corn starch in a bowl. Set aside.
4. Add 5 large eggs and 125g caster sugar to the Oon Halo Core mixing bowl. Fit the bowl onto the Ooni Halo Core mixer body along with the Dual-Geared Whisk attachment.
5. Start the mixer and whisk at 70% (7 fully lit segments on the Halo Core dial) for 6 minutes until the mixture has tripled in volume and looks pale and airy. 
6. Remove the mixing bowl from the mixer. 
7. Sieve a third of the flour mixture into the egg mixture. Using a silicone spatula, fold the dry ingredients into the egg mixture until only a few dry streaks remain. Repeat another two times with the remaining dry ingredients. 
8. Take two heaped tablespoons of the cake batter and add it to the bowl of melted butter. Stir vigorously to combine. This helps the melted butter to mix evenly into the cake batter, so ensure it’s fully incorporated. 
9. Add the butter mixture into the mixing bowl and lightly fold it into the cake batter until just combined, avoid overmixing. 
10. Divide the batter between the two cake tins and then tap the cake tin firmly on the counter to remove any large air bubbles. 
11. Place in the oven and bake for 15-20 minutes until the surface of the cake is lightly browned and a skewer inserted into the centre comes out clean. 
12. Remove the cake from the oven and leave to cool in the tin for 10 minutes, then run a knife around the edge of the tin and invert the baking tin on a cooling rack to release the cake. Leave to cool completely. 

Mascarpone cream

1. Add 1-2 inches of water to the medium sized pot and bring it to a simmer.
2. Add 4 egg yolks and 50g caster sugar to the heatproof bowl. 
3. Place the bowl over the pot of simmering water, ensuring that the bowl’s bottom does not touch the water. 
4. Whisk the egg yolk mixture continuously for about 3 minutes until it looks pale, has tripled in volume and the sugar has completely dissolved into the mixture. Remove from the heat. 
5. Add 500g mascarpone and 80g icing sugar into the Ooni Halo Core mixing bowl. 
6. Set the mixer to 50% (5 fully lit segments on the Hao Core dial) and whisk for 1 minute. Use the Clear Splash Guard to avoid a cloud of icing sugar. 
7. Add the egg yolk mixture and whisk for another 30 seconds at 50%. Scrape the sides of the mixing bowl down partway through. 
8. Increase the mixer speed to 70% (7 fully lit segments on the dial) while gradually streaming 150g of whipping cream through the spout. Whisk for about 1 minute or until the mixture holds a soft peak. Do not overwork the mixture as it will continue to firm up as you assemble the cake.

Assemble

1. Combine the espresso and coffee liquor. Set aside.
2. Place one cake layer onto your cake board, then place the ring of your 9” springform tin around it. If using acetate paper, line the 9” springform tin with it now.
3. Carefully line the edge of the cake with the sponge fingers, so that it creates a ring of vertical sponge fingers around the cake to support the mascarpone cream.
4. Drizzle 5 tablespoons of the espresso liquor mix evenly over the cake layer. 
5. Spoon half of the mascarpone mixture over the cake and, using a spatula, spread it into an even layer. 
6. Place the second cake on top of the mascarpone layer and repeat steps 4 and 5. 
7. Dust the cake with 2 tsp of cocoa powder using the sieve, then place the cake (still in the cake ring and acetate!) into the fridge to chill completely — minimum 2 hours, but ideally overnight.
8. Remove from the fridge and serve cold. 

Tips (if applicable):

• Ooni Halo Core speed dial, explained: Each display light segment on the mixer indicates a speed increase of 5% when half lit and 10% when fully lit.
• Be careful not to overmix the cake batter. This is most important when adding dry ingredients and butter by hand. You want to keep as much air in the mixture as possible. 
• Don’t open the oven too early. Leave it shut as your sponge cooks until at least the 12 minute mark or you risk the cake collapsing.
• Avoid a face full of sugar. When adding icing sugar to your mixer, use the Clear Splash Guard to avoid a cloud blowing back up in your face, or increase the speed gradually. 
• Assemble the cake on the surface you’re serving it on. It doesn’t transfer well, so keep this in mind when choosing your cake board/stand.
• Use acetate paper to stop your sponge fingers breaking. If you don’t have it, you can assemble it (with care) directly into the springform tin ring.