Preheat oven to 180C / 350F / 160C fan-forced. Line a cookie tray with baking paper.

In a medium bowl, whisk together the flour, sugar and coconut to disperse evenly, then add the melted butter and mix through.

Press the mixture into the base of the lined tin and bake for 28-30 minutes until starting to turn golden on top then set aside to cool down.

In the bowl of stand mixer with whisk attachment, whisk the egg whites to soft peaks.

Once it reaches 130C / 260F on the thermometer, take it off the heat. Move quickly at this point so the syrup doesn't cool down too much.

Turn the whisk on again to start beating the eggs to stiff peaks.

Place the gelatine mixture in the microwave and heat for 20 seconds. Stir well, then add it to the sugar syrup, carefully stirring it through. Be careful as it may splatter and will froth up

With the mixer still running on low-medium, slowly pour in the sugar syrup in a steady stream down the side into the egg whites, until all incorporated. Not too quickly or the egg white will split.

Turn the mixer up to high and beat for 10-12 minutes until doubled in volume. You'll know its ready when it runs slowly off the whisk in a thick stream that doesn't disappear for a while.

Brush a little oil around the inside edges of the tin with the cookie base in it.

Now carefully spread the marshmallow mix over the cookie and jam base (a greased spatula will assist here).

Dot the top with spoonfuls of raspberry jam, then run the blade of a dinner knife through it back and forth to make it streaky.

Allow it to set for at least 4 hours (overnight is better) before slicing