Hazelnut meringue layers

These layers hold up a rich buttercream and stay slightly chewy inside. They are meringue with ground hazelnuts folded in. The usual failure is a layer that sticks and bends, or one that is overbaked and snaps when you cut it. Both come from the same cause: the water in the foam did not leave slowly and evenly.

Ingredients and what each one does

• Egg whites make the foam, which is the skeleton. Any fat, even a trace of yolk, stops them from whipping up.
• Sugar, fine caster sugar rather than icing sugar, stabilises the foam and holds water. Icing sugar contains starch, which interferes with whipping.
• Ground hazelnuts add flavour and a softer texture, but their oil is heavy for the foam, so they are folded in gently.
• A little flour binds moisture so the layer does not weep into the cream.

How to make it

1. Use a glass or metal bowl wiped with vinegar. Plastic holds a film of fat that ruins the foam.
2. Whites at about 21 °C. Start on low speed with a pinch of salt.
3. Add the sugar in small portions and keep whipping until it has fully dissolved. Sign: rub a little foam between your fingers and you feel no grains, and the peaks stand stiff. With a hand mixer this can take 15 to 20 minutes.
4. Mix the nuts with the flour and fold them in from the bottom up until the streaks disappear. Stop there, each extra turn knocks out air.
5. Spread the mixture in discs about 1 to 1.5 cm thick. Thicker discs do not dry through in the middle.
6. Dry at about 130 °C for around 45 minutes (20° lower with a fan). Sign: the layer lifts off the paper, the surface is dry to the touch and the colour is golden cream. Pure white meringue needs 100 °C or less, but here a golden colour is fine.
7. Do not let it cool in the oven, it dries out. Take it out and cool on the paper.

What can go wrong

• Sticks to the paper. Underdried. Give it another 10 to 15 minutes at the same temperature.
• Brown droplets on the surface. The sugar did not dissolve. Whip longer, do not raise the heat.
• Collapsed and weeping. Too little sugar, or the foam was over-mixed after the nuts went in.
• Cracks when cut. Overbaked or too thick. Cut with a serrated knife with a sawing motion.

Substitutions

Almonds instead of hazelnuts give a paler layer and a milder taste. Blanched nuts give a cleaner colour, nuts with skins are darker and slightly more bitter.

Storage

Airtight and dry for a few days. Once assembled with buttercream the layers soften over several hours, which is what you want.