Heat the oven to 200C/180C fan/gas 6. Put the butter, caster sugar and 50ml water in a heavy-bottomed saucepan and set over a low heat until the butter has melted and the sugar has dissolved. Then turn the heat up to medium-high and allow to simmer for 15-20 mins until a light caramel colour. Add 1 tsp salt and stir again to make sure there are no sugar crystals. Stir in 80g of the toasted hazelnuts.

Line a 20cm square tin with baking parchment and lay the matzo sheets on top. You will need to break up one sheet to fill the gaps. Don’t worry if it’s not exact, you just want a layer of matzo covering the base of the tin. Pour the caramel mixture over the matzo, then carefully (because it will be hot) spread it out to cover the surface of the matzo. Bake for 10 mins.

Put the tin on a heatproof surface or wire rack and sprinkle with the chocolate drops. Wait 1-2 mins until they melt, then lightly spread them over the surface. Scatter with the remaining 20g of hazelnuts. Leave to cool to room temperature, then refrigerate for an hour or so, before cutting into large shards.