Preheat oven 180°C fan forced. Line base and sides 5cm deep, 18cm x 28cm (base) slice pan allowing a 2cm overhang at both long ends.

Combine the macadamia nuts, flour and brown sugar in a bowl. Add the butter, mix until well combined. Remove ¾ cup (175g) mixture. Press the remaining mixture evenly into the lined pan. Bake 15 minutes or until light golden around the edges.

Meanwhile, combine sweetened condensed milk, butter and golden syrup in a medium non-stick saucepan. Stir constantly over medium heat, for 6-8 minutes or until the caramel thickens (see tip).

Peel and slice the bananas into 1cm-thick rounds. Fold into the warm caramel then carefully spread over the warm base. Crumble over the reserved macadamia mixture. Bake a further 15 minutes until top is golden. Set aside to cool completely. Cut into pieces to serve.

You can cook the caramel in the microwave; combine the ingredients in a 2 litre heatproof microwave-safe bowl. Microwave uncovered on High/100%, whisking every minute, for 4-5 minutes or until the caramel thickens.

Slice will keep 1 week in the fridge.