Low-GL Snacks: Butter bean and mustard mash

1x 400g can butter beans, drained and rinsed
300ml vegetable stock
2 tablespoons olive oil
1 heaped teaspoon Dijon mustard
2-3 tablespoons chopped parsley
freshly ground black pepper

Put the beans in a heavy-based saucepan and pour in enough vegetable stock to cover. Bring to the boil, cover the pan, reduce the heat and simmer for about 15-20 minutes, until the beans have softened. Drain, reserving the stock.
Put the hot beans in a bowl and add the olive oil and mustard. Mash the mixture with a fork or a potato masher until is quite smooth. Stir in the chopped parsley and more olive oil, if necessary, to loosen the mixture. If the mash still seems too stiff, stir in a little of the reserved stock.