Melt butter and chocolate together. Let cool. Mix with ground almonds and flatten into one of those spring cake tins (which I lined at the bottom with oven paper - probably shoulda done the sides too.. opps!)
Put in fridge for about 15 minutes while you beat together the cream cheese, sour cream and Splenda. Then add the 4 eggs one at a time. Realize, like me, that you shoulda started with a bigger bowl as everything splatters all over the kitchen. Then mix in lime zest and lime juice.
In a separate bowl, whisk the 2 egg whites to soft peaks.. (I LOVE doing that!) and then fold into the first bowl. Pour over the base and bake for 1 hour and 20 minutes or so in the oven at about 150*C. I cooked mine longer cause the oven is a bit slow - and baked until it was brown on the top.
Take out of the oven. Run a knife round the side (especially if you didn't line it like I didn't!). Let cool. It'll deflate (awwww). Then unspring the spring thingie and turn out onto a plate. Chill maybe overnight or as long as you can wait....
Enjoy!