Break up the biscuits

Preheat an oven to 180ºC

Grease a springform tin and line with parchment paper

Fit the K-Beater to the machine

Add biscuit crumbs, sugar, butter and zest of 1 lime into the Mixer bowl

Attach the Mixer bowl to the machine and fit the splash guard

Start the machine on speed min and mix for about 4 minutes or until you reach a sand-like mixture

Press the mixture into the base of the tin in an even layer

Place into the preheated oven and bake for 10 minutes at 180°C

Let cool and reduce the oven to 160°C

Retrieve, clean the Mixer bowl and fit the Whisk Tool

Add egg yolks to the bowl

Start the machine on speed 2 and mix for 1 minute

Add condensed milk, zest and juice of remaining limes to the bowl

Mix on speed 1 and mix for 1 minute

Pour the lime mixture on to the biscuit base

Retrieve, clean the Mixer bowl and fit the Whisk Tool

Add egg whites and tartar into the Mixer bowl

Attach the Mixer Bowl to the machine

Start the machine on speed 4 and mix for 3 minutes, keep the machine running

Add caster sugar while the machine is running

Mix on speed 4 and mix for 3 minutes or until stiff peaks form

Spoon the meringue on to the lime mixture and spread to form a peak in the middle

Bake for 20 minutes at 160°C until the meringue is golden and toasted in places

Cool and chill in the fridge for at least 4 hours before serving

Serve