Preheat oven to 350 and a rack in the middle of the oven with another rack below it. Put a cookie sheet on the lower rack (to catch any drips).

Butter a 9" round (with 2 inch sides) cake pan. Line the bottom with parchment paper.

SAUCE:

Combine sugar, butter, cream in a small saucepan over medium heat. Stir until sugar has completely dissolved and the sauce is bubbling. Pour a scant 1 cup (about half the sauce) into the prepared cake pan, set aside the rest to serve with the pudding.

PUDDING:

Put the dates and baking soda in a small bowl and pour over the boiling water; set aside. Cream the butter, brown sugar, and vanilla in a large bowl until light and fluffy. Beat in the eggs a little at a time, sprinkling in a little flour after each addition. This will stop the batter from curdling.

Mix in the dates and their soaking water. Sift over the remaining flour and the baking powder. Fold them in gently but throughly. Stir in the chopped chocolate and espresso powder (if using). Pour the batter into the cake pan. Bake until the top is golden and firm and the sides of the pudding have shrunk away slightly from the sides of the pan; about 50-60 minutes. Cool on a wire rack for 15 minutes, run a knife around the edge of the pudding and turn out onto a serving plate.

Reheat the remaining sauce until bubbling. Spoon the sauce over thick wedges of hot pudding with a dollop of creme fraiche & sliced strawberries if you like.