Begin by separating the egg whites and yolks into two separate bowls.

Add half the sugar to each bowl. Whisk the egg whites until they double in volume and look frothy, and whip the yolks until they turn a pale yellow and have a creamy texture.

Gently fold the whipped egg whites and flour into the egg yolk mixture in three intervals, alternating each time to keep the batter as light and airy as possible—this is key for a soft, spongey cake.

Pour the batter into a cake pan that matches the size of your biscuit tin. Bake for about 10-15 minutes; this layer should be thin, around 1-1.5 inches, so it complements the mousse perfectly without overpowering it.

While the cake is baking, mix the three types of milk—condensed milk, evaporated milk, and heavy cream—until well combined.

Once baked, place the cake layer into the biscuit tin. Poke holes with a fork and pour the milk mixture over the cake, letting it soak in. Tip: It’s best to soak the cake once it's in the tin; the cake becomes delicate once soaked and might be tricky to move.

In a saucepan, combine sugar and water. Important: Avoid using a spoon to stir, as it can lead to crystallization. Instead, gently swirl the pan to ensure all the sugar is covered.

Set the pan over medium heat, swirling every few minutes to help the sugar dissolve and caramelize evenly.

If crystals form on the sides of the pan, brush them away with a damp pastry brush to keep the caramel smooth.

Once the caramel reaches a medium-dark amber, carefully pour in the warmed cream (it will bubble up) and whisk until fully combined.

Add the butter and cook for another 1-2 minutes while whisking. Remove from the heat, add a pinch of salt, and give it a final stir.

Let it cool slightly, then blend with a stick blender or regular blender to fully emulsify the butter and achieve a silky, glossy sauce.

Dry roast the peanuts until golden brown, then set them aside.

In a saucepan, cook the water and caster sugar on medium heat, without stirring, until the sugar dissolves.

Add the roasted peanuts and keep stirring. At first, the sugar will crystallize around the peanuts, but don’t worry—keep stirring, and within 5-7 minutes, the sugar will melt again, coating the peanuts in a caramelized layer.

Be careful not to overcook, as this can lead to burning. Once the caramel forms, pour the peanuts onto a baking sheet and let them cool for 30 minutes until hardened. Then, break them into smaller pieces for easy sprinkling.

Combine milk, cream, and butter biscuits in a saucepan. I recommend using the two plain biscuit types from the butter cookie tin (vanilla ring and country-style), avoiding flavored ones for a more classic taste.

Cook on low heat for 5 minutes, allowing the biscuits to soften in the milk mixture. Use a spoon to break down the biscuits until there are no lumps left and the mixture becomes smooth (it might look odd but don’t worry).

Remove from heat and add the white chocolate. Let it sit for a minute to melt, then whisk until it turns into a smooth, thick ganache.

While it cools, whip the remaining cream to medium peaks—don’t overmix, as it still needs to be folded with the biscuit ganache.

Once the ganache has cooled, fold it gently into the whipped cream with a spatula. Tip: Make sure the ganache isn’t warm; otherwise, it could melt the whipped cream.

Place the tres leches cake layer in your tin and pour a layer of salted caramel sauce on top.

Sprinkle the peanut praline over the caramel, keeping it light so it doesn’t overpower the cake.

Spread the butter biscuit mousse on top, smoothing it out evenly.

Chill the cake in the fridge for at least 4 hours to let the layers set perfectly.

Before serving, top the cake with butter biscuits arranged to resemble the original look of the tin, close the lid, and get ready to surprise your guests!