Preheat over to 350ºF/180ºC and line a large oven tray with baking paper.
Put the coffee beans into food processor and process for 2 minutes until finely chopped.
Be sure to measure the flour carefully without compacting it into the cups. Then sift flour, baking powder and cinnamon.
Beat the butter, sugar and vanilla with an electric mixer until pale. Add eggs one at a time. (To avoid a crumbly dough, use extra large eggs. Please read the notes below!)
Stir sifted flour mixture (reserving a few tablespoons) into butter mixture along with ground coffee, coconut, hazelnuts and chocolate and mix until well combined. If the dough is very sticky, add the reserved flour a little at a time. Please read the notes below!
Knead lightly and form into two logs about 10in/25cm long on the baking tray and pat down to about approx ½ inch/1½cm in thickness. Bake for 25 minutes. Cool completely - about 1 hour.
Reheat the oven to 300ºF/150ºC. Line two baking trays with baking paper. Using a serrated knife cut logs into approx. ⅓ inch/1cm slices and arrange cut side down on baking trays. Please check the notes below for tips on slicing.
Bake for 15 minutes until firm to touch. Cool on a wire rack.
Updated A couple of readers have messaged me to say the biscotti were crumbling when cutting so here is a few extra notes
Use extra large eggs - eggs that are 2 oz (58 grams) or 24 ounces (700 grams) per dozen eggs. It is better to err on the larger side of eggs with these biscotti.
Always grind your own coffee beans as per the recipe. Don't use preground, it is way too fine.
Hold back a couple of spoonfuls of flour if you think it is looking dry. You can always add more flour but you can't take it away.
Use a thin bladed, serrated knife to cut the biscotti. Cut slowly and carefully. Some will break, that's inevitable but that's the cook's treat!