This is also very good with a baked potato.
1-2 tablespoons low-fat natural Yoghurt
1/2 tablespoon fresh mint, finely chopped
1/2-1 clove garlic, peeled and crushed or finely chopped (optional)
salt and freshly milled black pepper
squeeze of lemon juice
Mix everything together and season to taste with salt, freshly milled black pepper and lemon juice.