Preheat the oven to gas 7, 220°C, fan 200°C. Put the walnuts on a baking tray and bake for 5 mins.
Put the cheeses in a lightly oiled baking tin, then bake for 5 mins until slightly melted; halve. Meanwhile, whisk together the mustard, lemon juice and honey in a small bowl. Season, then whisk in the oil with 2 tsp water until combined.
To serve, divide the grapes, beetroot and salad leaves between 4 plates and drizzle over the dressing. Top each with a baked goat’s cheese half and a few walnuts. Delicious with crusty bread.