Preheat your oven to 165°C / 145°C fan / 325°F (165°C) / gas mark 3. Lightly butter a baking tray and line it with baking parchment.
Spread the torn marzipan pieces evenly on the prepared tray. Toast for 10–12 minutes, until they are a beautiful golden brown.
Transfer the hot, toasted marzipan into a saucepan with the milk and cream.
Bring the mixture to a boil over a medium heat.
Carefully use a hand-held immersion blender to blitz the mixture until smooth. Be cautious as the liquid will be very hot.
Cover the pan and allow the flavours to infuse for at least 1 hour. For the most intense flavour, let it infuse overnight in the fridge.
Strain the mixture through a fine-mesh sieve into a clean saucepan, pressing on the solids to extract all the liquid.
Discard any remaining lumps and bring the infused liquid back to a boil.
In a separate large bowl, whisk together the egg yolks, sugar, and sifted cornflour until pale and combined.
Slowly pour about half of the hot marzipan milk into the egg yolk mixture, whisking constantly. This tempering step prevents the eggs from scrambling.
Pour the tempered egg mixture back into the saucepan with the remaining marzipan milk.
Cook over a low heat, whisking continuously, for 5-10 minutes. The custard is ready when it has thickened enough to coat the back of a spoon and you can see steam rising.
Do not let it boil, or it will split.
For an extra-smooth finish, pass the finished custard through a fine-mesh sieve one last time.
Don't discard your leftover egg whites! They are perfect for making homemade meringues, macarons, or a light and airy angel food cake.
