1. Preheat the oven to 170°C and line three large baking trays with greaseproof paper.
2. Whip together the butter, caster sugar, and brown sugar.
3. Next, crack in the egg and whip again until light and fluffy. It might look like the mixture has scrambled but don't worry, keep going.
4. Add in the dry ingredients and mix until you achieve a soft dough.
5. Fold in the chocolate chips and crushed Ready Salted crisps. Mix again.
6. Wrap the dough in clingfilm and refrigerate for 30 minutes.
7. One by one, take tablespoons of dough and roll into balls, then roll into more crushed up Ready Salted crisps. Place onto the baking trays. Remember, these will spread so keep them a good distance away from each other.
8. Bake for 14-16 minutes for soft cookies and 18-20 minutes for crunchy cookies.
9. Remove from the oven and allow to cool on a wire rack.