Put the blackberries in a small bowl and pour over the vinegar. Stir, then set aside for about 15 minutes. Meanwhile, put the coriander and caraway seeds in a small pan over a low heat for 1-2 minutes.
When they smell aromatic and toasted, tip into a pestle and mortar and roughly crush. Lightly toast the mixed seeds in the same pan for 1-2 minutes.
In a large bowl, mix together the salad onions, spinach, parsley, toasted seeds and crushed spices. Scoop the blackberries into the salad, leaving the vinegar behind.
Whisk the oil, mustard and honey into the leftover vinegar to make a dressing; season. Spoon the dressing over the salad. Toss everything together well.
Crumble over the goats’ cheese, toss one last time, then transfer to a platter or serving plates and eat straight away, with a slice of crusty bread if liked.