1. Preheat the oven to 150°C / fan 140°C / gas mark 2. Line a 9" x 9" baking tray with baking paper.
2. To make the base, sieve the flour into a bowl and add the caster sugar and salt, then rub in the butter until a crumbly dough is formed. This can also be done in an electric stand mixer.
3. Press into the lined tin and bake for 35 minutes or until the top of the shortbread looks a pale gold colour.
4. To make the peppermint filling, sieve the icing sugar into a bowl and add the peppermint essence. Add approximately 12 dessert spoons of water to the mixture until a thick paste is formed. Add drops of food colouring until you reach the desired shade of green.
5. Once the shortbread is cooked and still warm, spread over the peppermint filling, leave this to set in the fridge for 1-2 hours, or until the green peppermint filling has slightly stiffened.
6. Melt the chocolate in short 30 second bursts in the microwave and pour over the top of the peppermint filling until it is evenly coated.
7. Leave to set in the fridge for at least 30 minutes. The peppermint filling isn’t as stiff as the typical millionaire’s caramel filling so ensure that the squares are kept in the fridge.
CHARLOTTE SAYS “I’m a bit of a baking addict and most of my recipes are family recipes that have been passed down to me from my grandma. She gave me her old recipe book, some of which she wrote when she was in her 30’s - she’s now 73!”