I am compiling a list of the best black puddings. It began in Spain when I encountered my first morcilla de Burgos, a rich, spiced black sausage bulked up with rice. I was smitten. No black pudding could compete with this, I thought. But then I moved to Cumbria and in the flat hinterland of the Solway plain I found a butcher who made trays of the black stuff, studded with nuggets of fat the size of a child’s thumb.