Recipe: 'The best millionaire's shortbread I have ever tasted...'

Telly chef James Martin explains where this millionaire's shortbread recipe comes from: "For this recipe I have to thank Kj, the head chef and owner of the Mountain Cafe in Aviemore.
"Kirsten Gilmore is a long way from her native New Zealand but now has a reputation for food, service and kick-ass coffee (in her own words!) with an amazing view of the Cairngorm Mountains in Scotland.
"You have to order the fish chowder and the sweetcorn fritters and, without a doubt, the best millionaire's shortbread I have ever tasted. She kindly gave me her recipe, so here it is for you."
For the biscuit base:
300g salted butter, softened
200g dark soft brown sugar
350g plain flour
125g cornflour
For the caramel filling:
1 x 397g jar dulce de leche
250g salted butter
150g caster sugar For the topping:
400g dark chocolate (70% cocoa solids), broken into pieces
100g salted butter
- 1. Preheat the oven to 170°C (150°C fan)/325°F/gas 3.
- 2. To make the biscuit base, put the butter, sugar and both types of flour into a large bowl. Use your fingertips to rub the butter into the other ingredients until the mixture looks really crumbly. Press the mixture into a 23 x 30cm loose-bottomed cake tin (no need to line) and use a palette knife to even out the surface. Bake for 20 minutes, then remove from the oven and cool in the tin on a wire rack.
- 3. To make the caramel filling, combine the dulce de leche, butter and sugar in a large saucepan over a medium heat. Whisking the mixture, bring to the boil (be careful as the mixture will be extremely hot).
- 4. Pour evenly over the biscuit base, cover and leave to set for at least four hours or overnight at room temperature.
- 5. To make the topping, put the chocolate and butter into a medium heavy-based pan and gently heat. Once everything has melted, whisk to combine. Cool slightly, then pour over the caramel and level with a palette knife. Cover, then leave to set overnight at room temperature.
- 6. Cut into 12 squares to serve.
James Martin's Islands To Highlands by James Martin, photography by Peter Cassidy, is published by Quadrille.