Easy No-Bake Key Lime Pie (minus the Key Limes!)

I like a good Key Lime Pie as it´s a bit like cheesecake (at least the ones I´ve tried anyway!) and as I had some digestive biscuits lying around that needed eating up, it was my excuse to make this tangy yet sweet dessert. Key Lime Pie is an American dessert and is usually made with key limes (hence the name) but of course if you can´t get Key limes, ordinary limes will do. They are also usually baked and even though I tagged it under baking, this recipe is super easy as you don´t have to actually do any baking!!According to Wikipedia, it is usually also topped with a meringue topping but again the ones I tried haven´t. So here´s the recipe, adapted from one of the editions of Better Homes & Gardens Cook book, enjoy!

Ingredients (makes about 8 slices)

100g oat digestives (or similar biscuits-I think gingernuts would be great for this recipe if I could buy them!)
50g butter
1/2 cup of lime juice (about 4 limes)
1 cup of whipping cream (2nd cup optional)
1tsp grated lime zest
1 1/4 cups of condensed milk

Method
1.Process biscuits in food processor till very fine crumbs.
2. Melt butter in pan over low heat and add to biscuit crumbs,mix, then press into cake tin to form biscuit base, place in fridge.
3. Mix condensed milk, lime zest and lime juice in a bowl.
4. Beat whipping cream with an electric hand whisk till it forms soft peaks.
5.Fold into condensed milk and lime juice mixture, then spoon on top of biscuit base.
6.Freeze for 2-4 hours. If desired, whip up extra cup of cream and place on top and grate some lime zest on top for decoration.