Start by melting your chocolate. Break it into rough pieces and heat in a bowl over a bowl of simmering water. Put to one side to cool for a couple of minutes.
Whisk your egg whites in a stand mixer until they form stiff peaks. Add your teaspoons of Splenda and whisk again for another minute or so until the egg whites are lovely and glossy.
Mix your egg yolks into your melted chocolate with a wooden spoon.
Going carefully, slowly fold your egg whites into the chocolate and egg mixture with a metal spoon. Gently cut through and stir the mixture, retaining as much of the air in the mix as possible.
Spoon the mix into serving dishes: either one big one or individual ramekins/martini glasses like these.