Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4
To make the base use a food processor to whizz up the digestive biscuits and ginger nuts into crumbs, or you can put them in a bowl and bash them with a rolling pin
Mix the melted butter into the biscuit crumbs and press them into a loose bottomed 23cm/9" tart tin
Bake the biscuit base for 10 minutes, take out and set aside to cool
To make the filling, whisk the egg yolks together with an electric mixer for a few minutes
Then whisk in the condensed milk
Add the juice and the zest of the limes and whisk the mixture for a few minutes
Pour the lime filling into the base and bake it for 15 minutes or until it is set, but it still wobbles a little. Let it cool completely
Whip up the cream with the icing sugar and vanilla, pipe or dollop it on top of the cooled pie then sprinkled over the lime zest
Serve immediately and store any leftovers in the fridge for 2-3 days
Notes
You can use either butter or a baking spread for the biscuit base.
I used a combination of digestive biscuits and ginger nut biscuits for the base, if you want to omit the ginger then you can use all digestive biscuits. Or if you want a stronger ginger hit, use all ginger nut biscuits. You could even add some ground ginger to the biscuit crumbs if you're a big ginger fan!
I piped the whipped cream on top of the tart using a Wilton 1M and Wilton 6B nozzle. You can also simply dollop it on top.
You must use condensed milk for this recipe, evaporated milk will not work.
A US cup measure or a shot glass make handy tools for pressing the biscuit base into the tin and up the sides evenly.
Although I provide cup measurements, I highly recommend weighing your ingredients out using digital kitchen scales*. It is the most accurate way to measure ingredients and will ensure the best results. Digital scales are very low cost and can be purchased for around £12 ($16.50) .
For teaspoon (tsp) and tablespoon (tbsp) measurements, please use measuring spoons* and not the type of spoons you eat with. Again this will ensure accuracy and provide the best results.