The ultimate indulgent square, a Millionaire’s Shortbread with Tahini added to the Caramel for a subtle nutty flavour. The top layer of dark chocolate has Olive Oil added to it for a glossy sheen, while the biscuit base has oats added to it for a slightly different texture. We recommend you leave them to cool fully in a fridge before slicing them into square with a hot knife.
Place the tins of condensed milk in a large saucepan and cover with water. Bring to the boil and cook for 2 hours, uncovered, making sure the tins are always covered with 6 cm of water to prevent them popping open.
Remove from the water and leave till cool enough to touch. Open and scoop out the contents, which should be a deep caramel brown colour and place in a bowl. Add the tahini and mix until well combined. If the caramel is very hot, it will split the tahini and make it go grainy.
Whilst the caramel is cooking make the base. Heat your oven to 160C fan / 180C non-fan / gas mark 4. Combine the butter and golden syrup in a small pan and place on a low heat to melt. Line a deep 20cm x 20cm tin with baking paper, making sure the paper comes up the sides. Mix the flour, sugar, oats, bi-carb and salt in a large bowl, then pour over the butter mixture and stir with a large spoon so the butter is completely absorbed. Spoon into the tin and use the spoon to spread out the mix and push into the corners, trying to create a level surface. Bake in the oven for 15 minutes, or until golden brown on top, then take out and allow to cool.
Whilst the caramel is still warm, pour over the base and used a spoon or spatula to spread out evenly over the top. Leave for a few hours to completely cool and set.
Break the chocolate into small pieces and place in a small heat proof bowl. Set over a small pan of barely simmering water and allow to gently melt, stirring occasionally with a spatula. Once melted, remove from the pan, add the olive oil and stir to mix. Pour over the caramel, tilting the tin so it spreads to the corners whilst leaving a smooth surface. Leave until completely solid and set, then turn out and cut into squares. You can speed this last step up by chilling in the fridge, but the chocolate will lose its glossy sheen.