Duck blackberry and chicory salad

Preheat the oven to 200?C/gas 6. Seal the duck breasts in a frying pan then transfer to a roasting tin and cook in the oven for 9 minutes.2. Remove from the oven and allow to rest for 5 minutes.3. Meanwhile, place the Dijon mustard, sugar and vinegar in a bowl. Whisk together, then gradually add the walnut oil. Add a third of the blackberries to the dressing, then mash to combine.4. Tear the heads of chicory apart, then in a medium bowl toss with half the dressing and the hazelnuts.5. Slice the duck thickly.6. Divide the chicory between 2 plates and top with the duck. Sprinkle the blackberries over and drizzle with the remaining dressing.