To make 'brownies in a jar' you'll need a 1 litre glass jar.
In a small bowl, mix the plain flour, salt and baking powder together.
Carefully spoon half of the flour mixture into the bottom of the glass jar. Gently move the flour around so that you have an even layer.
Spoon the cocoa powder on top of the plain flour in the jar and spread around to create another even layer.
Spoon the remaining flour mixture over the top.
Continue to create the layers in the following order - brown sugar, caster sugar, milk chocolate chips, white chocolate chips and finally walnuts.
Close the lid of the glass jar (if you have any extra space at the top of the jar, simply top up with extra walnuts).
Print out our free recipe gift tag and attach to the jar with a ribbon (see notes). I