Pre-heat the oven to 150Cfan. Line the base of a 900g loaf tin with parchment paper and gease the sides.

Whisk the butter and sugar together until really light and fluffy, at least 5 minutes. Crack the eggs into a bowl and whisk lightly with a fork. Add a tablespoon of egg at a time to the butter mixture, scraping down the sides of the bowl occasionally. It's worth taking time with this as this will ensure a super light cake.

Blitz the hazelnuts in a food processor, don’t over mix otherwise they will become claggy. Combine the flour and baking powder with the ground hazelnuts. Fold in 3 additions to the cake batter.

Peel 2 pears, remove the core and chop into small pieces. Cut the third pear in half and slice finely into 5 length ways (this is for the top of the cake) peel the remainder and chop and add to the rest. Fold into the cake batter with the chocolate.