Blueberry & pretzel cookies

Heat oven to 190C/170C fan/gas 5. Line 2 baking trays with baking parchment. Tip the butter, sugars and vanilla into a bowl. Beat with a hand-held electric whisk until pale and fluffy. Add the egg and beat again. Tip the flour, bicarb and a pinch of salt into the bowl, and use a spatula to mix together. Add the blueberries, pretzel pieces and chocolate chunks, and mix again until everything is combined.

Scoop golf-ball-sized mounds of cookie dough onto the baking trays, making sure you leave plenty of space between each one. (You should fit 4-6 cookies on each tray, so you’ll have to bake in batches to make the total 20 cookies.) Can be frozen at this point – simply defrost in the fridge before baking. Bake for 18 mins, swapping the trays around halfway through.

Remove the trays from the oven and leave to cool for 10 mins before transferring to a wire rack, then bake the second batch. Continue until all the cookies are baked. Will keep in a cookie jar for up to 1 week.