For the dressing: Whisk together the vinegar, mustard, honey, jam, 1/2 teaspoon salt and 1/4 teaspoon pepper in a small bowl. Whisk in the oil in a slow stream and continue whisking until the dressing is emulsified.
For the salad: Toss together the spinach, blackberries, onions and Candied Walnuts in a large salad bowl. Drizzle with the dressing and toss. Using a vegetable peeler, shave some cheese over the top.
Yield:1 1/2 cups
Line a baking sheet with parchment paper and set aside.
Melt the butter in a medium saucepan over low heat. Add the walnuts and stir to coat. Raise the heat to medium, add the sugar and cook until the sugar is dissolved and caramelized, stirring often, about 5 minutes. Stir in the cinnamon, 1/2 teaspoon salt and 1/4 teaspoon pepper, then transfer the mixture to the baking sheet. Spread the nuts in a single layer. Let the walnuts cool until hardened, about 15 minutes.