2.Process biscuits to fine crumbs. Melt 125g of the butter in a small saucepan or in a heatproof bowl in the microwave. Stir in biscuit crumbs. Press over base and side of tart tin. Place on an oven tray. Refrigerate for 1 hour or overnight until firm.
3.Place 250g mascarpone, the caramel top ‘n’ fill and sea salt in a large bowl. Whisk until smooth and soft peaks form. Spread over biscuit base. Refrigerate for 2 hours.
4.Melt remaining butter in a large non-stick frying pan over high heat. Thickly slice bananas lengthways; sprinkle with sugar. Cook banana for 30 seconds on each side or until caramelised (see tip).
5.Top tart with caramelised banana and coconut chips. Serve with remaining mascarpone.
If you have one, you can use a kitchen blowtorch to caramelise the bananas in step 4.
The biscuit base can be made a day ahead; refrigerate until required. The tart can be made to the end of step 3 a day ahead; cover and refrigerate. Cook bananas just before serving.
You can use 3 or 4 finger bananas instead of regular bananas.