Mexican Pastel Imposible aka Chocoflan

You will need a 27-cm/11-in bundt tin, liberally greased with unsalted butter.

1. Start with the salted caramel sauce. Add the caster sugar to a large, heavy-bottomed saucepan, place over a medium heat and allow it to melt into a lovely, golden-brown liquid.
2. If you find patches of your sugar are caramelizing but others aren’t, swirl the pan to gently coax the unmelted sugar into the hot patches but avoid the temptation of using any utensils to mix.
3. Once the sugar has melted and is a lovely, rich golden brown, remove from the heat and add the unsalted butter. Use a balloon whisk to give it a really good mix to emulsify to a smooth liquid.
4. Slowly go in with the double cream whilst continuing to mix. Once all the double cream has been added, place the pan over a medium heat and let it continue to cook for a few minutes.
5. Remove from the heat and mix in the vanilla and salt before transferring to a large bowl. Cover and leave to cool at room temperature for 1 hour before popping in the fridge to set lightly.
6. Once the sauce is lukewarm, preheat the oven to 160°C fan/180°C/gas mark 4.
7. Pour 100 g of the cooled salted caramel sauce into the base of the prepared tin and spread using the back of a spoon to create an even layer. Set aside.
8. Next, make the flan. Add all the ingredients to a blender and blitz for 1 minute until smooth. Use a rubber spatula to scrape down the sides and base to ensure there are no lumps. Set aside.
9. Now for the sponge. Add the butter and both sugars to a stand mixer bowl and, using the paddle attachment, beat on a medium-to-high speed for a few minutes until light and fluffy. Once the butter is light and pale, add the eggs one at a time, beating well between each addition. In a separate medium-sized bowl, put the flour, baking powder, bicarbonate of soda, cocoa powder and salt and use a balloon whisk or fork to combine.
10. Add half of the buttermilk and a third of the flour mixture to the stand mixer bowl and mix on a medium-to-low speed until there are little-to-no visible flour streaks. Add the flour and remaining buttermilk in two more stages and stop mixing when everything is just incorporated to avoid a tough, dense sponge.
11. Transfer the batter to your bundt tin and level the top with the back of a spoon to create an even layer.
12. Place the tin in a large, deep roasting tray.
13. Gently pour the flan mix over the cake batter, either using a ladle or pouring over the back of a spoon.
14. Generously cover the top of the bundt tin with greaseproof paper, then tightly wrap and seal with a sheet of foil.
15. Pour boiling water into the roasting tin so the bundt is submerged by about 2.5 cm/1 in.
16. Carefully transfer the tray to the middle shelf of the oven and bake for 30 minutes, before rotating the tin and baking for a further 25 minutes — or until an inserted toothpick comes out clean.
17. Lift the bundt tin out of the water bath, remove the foil and greaseproof paper and allow the cake to cool completely in the tin.
18. Invert the Chocoflan onto a large serving plate. If you don’t instantly hear or feel a small thud, give it a little shake to help coax it out. If that fails, either use a blowtorch (gently and on a low fire) to warm the top of the tin or add a tea towel soaked in hot water to cover. If none of these options work, allow gravity to do its thing!
19. Once removed, place the Chocoflan into the fridge for at least 4 hours, but ideally overnight to chill completely.
20. Remove the cake from the fridge an hour before serving. Loosen the remaining salted caramel sauce with 1 tablespoon milk and then drizzle this all over the top.
21. Use a hot knife to slice and then scatter over a generous sprinkling of almond praline, if using, to serve.

FOR THE PRALINE

1. Place a large heavy-bottomed pan over a medium heat before adding the caster sugar. The key here is to not touch the sugar at all — just let it do its thing. We are essentially making a dry caramel so we want the sugar to become a nice, deep, amber colour before moving on.
2. Occasionally swirl the pan to distribute the sugar and any melted pockets of caramel.
3. In the meantime, add the nuts to a silicone mat and spread out to create an even layer.
4. Once the sugar has melted to a deep golden brown colour, pour the caramel over the nuts to coat and press gently to create an even layer. Set aside at room temperature to cool and set. Do not cool in the fridge.
5. When the praline is set hard, now you can use it as you wish. Keep it chunky for a crumb or add to a food processor, along with the vanilla bean paste and salt and blend until you reach a paste consistency.
6. Use immediately or store in an airtight container for up to 1 month.

Tip: Roast your blanched nuts before you use them for a more intense flavour.