For the meringue base, preheat the oven (electric oven: 100 °C/circulating air: 75 °C/gas: see manufacturer). Line a baking tray with baking paper. Beat the egg white until stiff, gradually adding sugar and 1 pinch of salt.
Continue beating until the sugar has dissolved and the mixture is shiny. Finally stir in lemon juice.
Chop nuts or biscuits and fold in. With a teaspoon, place about 24 heaps on the tray.
Leave to dry in a hot oven for about 2 hours. Take out and let cool down.