Whisk egg whites stiff peaks form. Gradually add the sugar, whisking continually until incorporated and the egg whites become thick and glossy. Add the chocolate and dates and fold through until combined.
Spoon into a lightly greased 22cm springform tin lined with non-stick baking paper. Bake for 45–50 minutes or until the outside is crisp.
Dust with cocoa and serve warm or at room temperature.