“The tang the Marmite brings to the caramel swirl running through these blondies is unusual, but I know you will be pleasantly surprised by the flavour,” says TV chef and restaurateur, Nisha Katona. “Just like a good salted caramel, the slight saltiness of the Marmite combined with the natural bitterness of the walnuts enhances and offsets the sweetness of the blondie.

“The caramel sinks into the batter slightly on cooking and you end up with a cinder toffee effect on top.”

You can use shop-bought caramel or dulce de leche if you prefer.

Ingredients:(Makes 12)

175g plain flour1⁄2tsp baking powder180g salted butter, melted and cooled280g light brown sugar2 eggs2tsp vanilla extract100g chopped walnuts

For the Marmite caramel:125g caster sugar30g salted butter100ml double cream2tbsp Marmite

Method:

1. First make the caramel, so it’s ready for when you need it. Put four tablespoons of water in a saucepan and tip in the sugar. Place the pan over a medium heat and stir gently until the sugar has dissolved, then leave it to cook for five minutes or so, without stirring, until it is a lovely golden colour.

2. Throw in the butter and let it melt in, then remove the pan from the heat and stir in the cream. It may spit at first, but keep stirring until you have a smooth sauce. Once fully combined, stir in the Marmite, transfer the mixture to a pouring jug and set aside to cool.

3. For the blondies, preheat the oven to 180°C/Gas 4. Line a 20 x 30 centimetre/eight x 12 inch brownie tin with baking parchment. Sift the flour and baking powder into a bowl.

4. In another bowl, stir together the melted butter and sugar. Once combined, stir in the eggs and vanilla extract. Add the flour mixture and fold in, then fold in the chopped walnuts. Pour the mixture into the prepared brownie tin and spread level.

5. If the caramel has set too much and is no longer pourable, heat it gently for a few seconds to loosen it up. Drizzle the caramel all over the top of the blondie, then stir it gently through with the handle of a spoon or a skewer to create a marbled effect in the batter.

6. Bake the blondie for about 30 minutes, or until the mixture is just set. Leave to cool for a few minutes in the tin before transferring to a wire rack to cool completely. Once cool, slice into 12 squares. Store in an airtight tin for up to three days.

BOLD: Big Flavour Twists to Classic Dishes by Nisha Katona is published by Nourish Books, priced £30. Photography by Martin Poole. Available now