750g/1lb 10oz chocolate hazelnut spread
425g/15oz plain flour, sifted, plus extra for dusting
1 tsp almond extract
1 tsp bicarbonate of soda
325g/11陆oz soft light brown sugar
200g/7oz roasted hazelnuts, chopped
1 tsp salt
1 tsp vanilla extract
200g/7oz chocolate-covered wafer biscuits, cut into cubes
400g/14oz dark chocolate chips
200g/7oz unsalted butter, softened, plus extra for greasing
2 free-range eggs, plus 1 egg yolk