Instructions

Making the base:

1. Place the biscuits in a large sandwich bag and crush with a rolling pin until they're small crumbs.

1. Mix butter in a large pan until melted, then turn the heat off.
2. Add crushed biscuits to melted butter, and stir to coat
3. Pour the biscuit mixture into a loose based tart tin
4. Press the mixture down (I use my fingers) to create an even, compressed base. Bake in the oven for 10 minutes then remove and cool while you make the filling.

Making the chocolate layer:

1. Whilst the base is cooling, break up your chocolate into small chunks and place over a pan of boiling water to melt
2. Stir continually until smooth, then remove from heat
3. Pour melted chocolate onto the base of the tart (don't worry if not completely cooled right now as the chocolate is hot anyway )
4. Smooth the chocolate so it is an even, flat layer using a spoon. Transfer to the fridge and allow to cool until the chocolate is no longer sticky.

Making the lime filling:

1. Mix the yolks in a large bowl with an electric whisk (or a strong wrist) until airy.
2. Add the condensed milk and lime zest and juice and mix for a further 4 minutes
3. Pour the filling onto of the chocolate, and bake the whole pie for 15 minutes; it should be slightly springy to touch once removed from the oven
4. Allow to cool completely - 3 hours or overnight.

Making the cream topping:

1. Once the pie is completely cooled, add the double cream and icing sugar to a large mixing bowl and whisk on high until it begins to form stiff peaks
2. Pipe, or spread, onto of your cooled pie
3. Sprinkle the top of the pie with lime zest and gratings of chocolate (optional)