To Make the Cake 

1. Preheat the oven to 180°C fan (350°F). Line three 6-inch round baking pans with parchment paper.
2. In a heatproof bowl, microwave the milk for 20 seconds, then add the instant coffee powder. Stir until fully dissolved and set aside to cool.
3. In a separate bowl, sift together the flour, cornflour, baking powder, and salt. Set aside.
4. In the bowl of a stand mixer fitted with a paddle attachment, cream the butter and sugar together until light and fluffy.
5. Mix in the vanilla extract and the coffee mixture until combined.
6. Add the eggs one at a time, beating well after each addition.
7. Add the dry ingredient mix and beat until the batter is smooth and well combined, scraping down the sides of the bowl if needed.
8. Divide the batter evenly among the prepared pans (about 295 g per pan, total 886 g).
9. For an even, flat top, wrap each pan with a damped level baking belt.
10. Bake for 20–25 minutes, or until a skewer inserted in the centre comes out clean.
11. Let the cakes cool in their pans for about 10 minutes, then un-mould and remove the parchment paper.
12. Transfer the cakes to a wire rack and cool completely before assembling.

To Make the Coffee Mascarpone Frosting

1. Mix the sifted the icing sugar and salt into a bowl and set aside.
2. In a saucepan over medium heat, add the double cream, vanilla extract, and instant coffee powder. Stir until the coffee has completely dissolved.
3. Pour the coffee-infused cream into a stainless steel bowl, let it cool for  5- 10 minutes , then cover,  and refrigerate for about 1 hour or until fully chilled.
4. Near the end of the chilling time, place the cold mascarpone cheese and the sifted icing sugar mixture into the bowl of a stand mixer fitted with a whisk attachment. Whisk until well combined.
5. With the mixer running, slowly pour in the chilled coffee cream and continue whisking until soft peaks form — similar to a soft ice cream texture.
6. Cover and refrigerate until ready to use.

To Make the Walnut Praline

1. Roughly chop the walnuts into small pieces and set aside. Prepare a sheet pan lined with a silicone mat or parchment paper.
2. Add the sugar evenly into a non-stick saucepan and heat over medium-high heat.
3. As the sugar begins to melt, gently swirl the pan to help it caramelise evenly — avoid stirring at this stage. You’re looking for a deep golden amber colour.
4. Once all the sugar has melted, give it a quick stir until smooth.
5. Add the chopped walnuts and stir until they’re fully coated in the caramel.
6. Carefully pour the mixture onto the prepared silicone mat or parchment paper. Quickly spread it out before it hardens.
7. Leave it to cool completely, then break it into pieces of your desired size.

To Assemble the Cake

1. Trim off the top of each layer if needed.
2. Place a non-slip mat on a cake turntable.  Then place the cake board on top to avoid it moving around.
3. Spread a dollop of frosting in the centre of the cake board, place a layer of cake in the middle.  Add two scoops of frosting onto it. I like to use an ice cream scoop.  Spread across the cake layer evenly.  Repeat the step of the second layer.
4. Place the last cake layer on top, bottom side up to create a perfect flat surface for the top of the cake.
5. To crumb coat the cake, spread a thin layer of frosting over the top and the sides, use a cake scraper to scrape off the excess. Chill the cake for 30 minutes to set.
6. Transfer the remaining frosting into a piping bag.
7. (Optional) Once the cake is chilled, you can transfer it from the cake board to your serving stand using two offset spatulas. Check out the video to see how I did it!
8. To complete the final coating, pipe a generous amount of frosting onto the top and the sides of the cake, then smooth out the surface. 
9. Decorate the cake as desired, pipe rosettes, or swirl using a piping tip, or use a cake spatula to create decorative lines on the sides and top (see my video). 
10. Place the walnut praline pieces on top.  Enjoy!