Place a pan over a medium heat and heat the oil, add the onion and
cook for 5 minutes, stirring occasionally, until soft but not browned.
Add the tomatoes, stock and honey to the pan, season to taste and simmer for 5 minutes.
Drain the haricot beans and add to the pan, giving everything a stir to combine, and cook gently for another 5 minutes.
Take off the heat and stir in the barbecue sauce, if using. Spoon the
beans over toast and serve warm.