Beat together the butter (200g) and sugars (90g soft dark brown sugar, 110g caster sugar) until fully combined and lighter in colour (this should take 2-3 minutes with an electric mixer).
Add the egg (1 whole large egg + 1 yolk) and the vanilla extract (1 tbsp) and beat until fully combined.
Sift in the dry ingredients (300g plain flour, 1½ tsp bicarbonate of soda, ⅛ salt) and mix together until fully combined.
Finally, mix in the chocolate chunks (100g) until they are evenly distributed in the mixture.
Roll the dough into a sausage shape about 5cm in diameter (I find it easiest to split the dough into two and make two sausages) and wrap it in cling film. You may find it easier to use the clingfilm to help you get an even sausage shape as the dough will be a little sticky. Refrigerate your dough for at least 1 hour (up to 5 days).
When you're ready to bake your cookies, preheat your oven to 190°C/170°C fan. Remove your cookie dough from the fridge and using a sharp knife slice it into round cookies about 1½cm thick. Place them onto a baking sheet (lined with greaseproof paper or a non-stick baking sheet). Leave space between each one as they'll double in size as they cook.
Push 3-4 Mini Eggs into each cookie. Put the remaining Mini Eggs into a pestle and mortar and bash them a few times to break them into large chunks. If you don't have a pestle and mortar then you could also put them into a plastic bag and bash them with a rolling pin.Push the broken pieces of Mini Egg into your cookies in any gaps around the whole ones.At this point your cookies should look overloaded with Mini Eggs (I've included a picture in the FAQs to show you what they should look like). Bake your cookies for 8-9 minutes until golden and crisp around the edges but still pale in the middle. If you're using two trays then swap them around after about 7 minutes. You may also want to rotate your trays at the same time to help the cookies bake evenly.
Once cooked, remove them from the oven. Leave them to cool for a few minutes on the tray before moving them to a wire rack to cool completely.
Calories: 276kcal | Carbohydrates: 33.6g | Protein: 3.1g | Fat: 13.9g | Saturated Fat: 8.5g | Sodium: 134.1mg | Fiber: 0.7g | Sugar: 23.1g
Any nutritional information provided is the estimated nutritional information per serving. Please refer to my guide to Charlotte’s Lively Kitchen nutritional information if you would like to learn more about how this is calculated.