Heat the oven to 180C/160C fan/gas 4. Butter a 20cm square cake tin and line with two strips of baking parchment. Melt the butter and chocolate in a heatproof bowl over a pan of simmering water (ensuring the bowl doesn’t touch the water) or in 20-second bursts in the microwave. Leave to cool slightly.

For the chai caramel, mix all the ingredients together in a bowl until the caramel has loosened.

Put the eggs and sugar in the bowl of a stand mixer fitted with the whisk attachment and beat for around 5 mins until pale and thick. Alternatively, do this using an electric whisk. Fold in the slightly cooled melted chocolate mixture using a spatula and, when fully combined, add the flour and cocoa powder. Mix until everything is combined and there are no streaks of flour. Pour into the prepared tin, drizzle over the chai caramel and gently swirl into the batter using a teaspoon.

Bake for 25-30 mins until the brownies are set at the edges with a slight wobble in the middle. If the brownies wobble a lot, they’re not done – bake for another 5 mins until the top has a shiny, papery crust and the sides are just beginning to come away from the tin. Leave to cool completely in the tin, then remove and slice into 16 squares to serve. Will keep in an airtight container for up to three days.