Cook the beans until they are no longer raw but still crunchy then strain. Heat some butter and a few drops of olive oil in a pan until butter has melted. Remove skin and pith of lemon and cut it into pieces. Add pieces and any juice to pan, stir and add beans. Stir thoroughly to coat the beans and then dish up.
Unfortunately I feel yucky today so were having toad in the hole instead of a roast, I might stretch and make some rice pudding or semolina for pudding though.