Tamarind caramel brownies

100g macadamia nuts, roughly chopped

250g unsalted butter, cubed, plus extra for greasing

275g dark chocolate, preferably 70% cocoa, chopped into small pieces

250g caster sugar

¼tsp flaky sea salt, plus extra for sprinkling

4 eggs, at room temperature, beaten

165g plain flour, sifted

1tsp espresso powder, or instant coffee granules dissolved in 1tsp hot water

For the tamarind caramel:

50g golden syrup (or maple syrup)

70g caster sugar

50ml double cream

20g unsalted butter

Large pinch of flaky sea salt

25ml tamarind paste