Lentil and bacon soup

If you poach a ham for Christmas this is a nice easy thing to do with the poaching liquid, if it's not too salty.  Indeed it is worth cooking the ham in a way that requires poaching (usually prior to roasting) so you get the stock.

20g butter
1 tbsp vegetable oil
4 rashers smoked streaky bacon
1 onion, chopped
2 tins 'green' lentils (they are more brown when you open the can actually)
1 litre lovely ham stock
2 tbsp finely chopped mint

Cut up the bacon and fry in the fats until a little coloured.  Add the onion and sweat until translucent.  Add the stock and the drained and washed lentils.  Bring to a boil, skim off any scum that rises to the surface and simmer for 15 minutes.  Add the mint, blend and season with pepper.