Image by Yuki Sugiura, from Cocoa: An exploration of Chocolate, with Recipes
A great way of using up bananas that have over ripened and you might be thinking of chucking out. Don’t worry if haven’t any spelt flour - just increase plain flour to 240g. And you can make them without tahini or use smooth peanut butter as a substitute.
150g / 5.oz unsalted butter
120g / 4.oz plain [all-purpose] flour
120g / 4.oz spelt flour
3/4 tsp baking powder
½ tsp bicarbonate of soda [baking soda]
½ tsp fine sea salt
280g / 10oz dark chocolate (70% cocoa solids), roughly chopped, with some biggish chunks and some small bits
1 very ripe banana, about 100g / 3.oz without skin
1 large egg
220g / 7.oz soft light brown sugar
40g / 1.oz granulated sugar
1 tsp vanilla extract
80g / 2.oz tahini (must be smooth and runny enough to run off a spoon easily)
flaked sea salt or fleur de sel, for sprinkling
Place the butter in a heavy, light-coloured pan and melt over a medium-high heat, swirling frequently, until the butter smells gorgeously nutty and has turned dark brown.
Remove from the heat and transfer to a mixing bowl or the bowl of a stand mixer, making sure you scrape in all the brown bits from the bottom of the pan (this is flavour!). Leave to cool for at least 5 minutes.
Meanwhile, using a fork or balloon whisk, whisk the flours, baking powder, bicarbonate of soda and salt together in a bowl to combine.
Add the chopped chocolate and stir to evenly distribute.
In a small bowl, mash the banana until smooth, then add to the cooled butter, along with the egg, both the sugars, vanilla and tahini. Whisk for a good 5 minutes until creamy and much paler than when you started –– this is a sign the mixture has aerated well.
Fold in the flour and chocolate mixture in 2 additions. Don’t overmix or beat smooth: dough with an uneven consistency delivers welcome texture to the baked cookies. Chill for at least 2 hours.
Preheat the oven to 170°C / 340°F / Gas mark 3 and line a large baking sheet with baking paper (you will need to cook these in batches).
Scoop heaped tablespoons of dough onto the prepared baking sheet (about 40–45g / 1.–1.oz each), leaving at least 5cm / 2in between them.
Bake for 6 minutes, then turn the baking sheet round and bake for a further 6 minutes or so until brown at the edges (the centre might look a little undercooked but it’s not).
Lightly sprinkle the cookies with the flaked salt while still warm. Leave on the baking sheet for 5 minutes, then transfer to a wire rack to cool.