Preheat the oven to 350 º F. Butter the inside of a 9 inch cake pan. Line the bottom with parchment paper, butter the paper, and dust the inside of the pan with flour; tap out the excess and set the pan aside.
Place the chocolate in a bowl and melt it in a microwave oven. Set aside the chocolate to cool. It should feel only just warm to touch when mix it with the rest of the ingredients.
Put the butter and sugar in a bowl of a mixer fitted with the paddle attachment and beat on medium speed for about 5 minutes, scraping down the sides of the bowl frequently until the butter is creamy and the sugar well blended into it. Add the eggs one at a time, beating for 1 minute after each addition. Reduce the mixer speed to low, pour in the cooled chocolate.
Add the flour, ginger and dates and mix it into the batter.
Scrape the batter into the pan, smooth the top and slide the pan into the oven. Bake for 20 to 25 minutes or until the cake rises slightly, top may crack a bit and the cake may not entirely set in center: when you test the cake by inserting a slender knife into the center, the knife will come out slightly streaked with batter which is what you want. Transfer the cake to a rack to cool.
When the cake, chill it in the refrigerator for an hour or two to make it easy to unmould. Turn the cake out, remove the parchment and invert the cake onto a serving platter so that it is right side up. Allow the cake to come to room temperature before slicing and serving.