Praline gives crunch between soft layers. The main problem is that it goes soft against the cream, because caramel absorbs water. The cause is lack of a barrier, not the nuts.
Ingredients and what each one does
- Hazelnuts are the base, for flavour and texture. Roasting brings out the aroma.
- Sugar caramelises and glues the nuts into a hard mass once cooled.
- Butter, a little, adds tenderness and makes grinding easier.
How to make it
- Roast the hazelnuts at 160 to 170 °C for about 10 minutes until they smell nutty. Rub in a towel to remove the skins.
- Make caramel from the sugar in a dry pan to a golden amber (about 170 °C) without stirring. Sign: it smells of caramel and the colour is like strong tea.
- Stir the warm nuts into the caramel so they are coated evenly. Add the butter and mix.
- Spread on baking paper in a thin layer and let it cool until fully hard.
- Grind coarsely in a blender or with a rolling pin. For a thin layer, press the crumb onto the sponge or into the cream.
- For a smooth paste, grind for longer: the nut oil comes out and the mass turns fluid.
What can go wrong
- Goes soft. The cream drew moisture from the caramel. Insulate with a thin layer of chocolate or ganache.
- Bitter. The caramel was overheated or the nuts were over-roasted.
- Sticky and will not harden. The caramel was undercooked and the sugar did not reach the right temperature.
- Grainy caramel. The sugar crystallised. Do not stir until it starts to melt.
Substitutions
Almonds, pistachios or peanuts work the same way with a different flavour. Less sugar gives a nuttier taste but a weaker crunch.
Storage
In an airtight container, dry, for 1 to 2 weeks. Inside a cake the crunch lasts only a short time, so assemble not long before serving.