To make the bars easier to slice straight from the freezer ... you may omit the salt in the recipe. Keep your keto chocolate ...

For this recipe you will need a 23x30cm/9x12in traybake ... Add all the remaining sponge ingredients, except the chocolate chips. Using an electric hand whisk, mix until light and fluffy.

They also help to make chocolate crackles — my childhood favourite ... I find this easier to slice if you do so before it sets too firmly. You could also spoon this into paper cases.