Step #2 Grease & line a 23x13x7cm cm (9x5x3in) loaf tin.
Step #3 Cream the butter & sugar.
Step #4 Add the eggs & vanilla, beating in well.
Step #5 Next fold in the melted & cooled chocolate, taking care to mix well but do not overbeat.
Step #6 You want the ingredients mixd: you don't want a light airy mass.
Step #7 Gently add the flour, alternately spoon by spoon, to which you've added the bicarb, with 250 ml of boiling water until you have a smooth & fairly liquid batter.
Step #8 Pour into the lined loaf tin & bake for 30 mins.
Step #9 Turn the oven down to 170C/gas mark 3 & cook for another 15 mins.
Step #10 The cake will still be a bit squidgy inside, so an inserted cake tester or skewer won't come out completely clean.
Step #11 Plaace the loaf tin on a rack & leave to get completely cold before turning it out.
Step #12 It improves if left for a day or so before eating.
Step #13 This cake will probably sink in the middle because of its denseness.
Enjoy the Dense Chocolate Loaf Cake - Nigella Lawson's recipe