Whisk together in a salad bowl:
      1 tablespoon red wine vinegar
      1 tablespoon minced shallots
      1/2 teaspoon Dijon mustard
      Salt and ground black pepper to taste
Add in a slow, steady stream, whisking constantly:
      2 tablespoons walnut oil
      2 tablespoons vegetable oil
Add:
      8 Belgian endives, washed, dried, cores removed, cut crosswise into 1/2-inch-thick slices
      1/2 cup walnut halves, toasted
      1/4 cup crumbled Gorgonzola cheese or other crumbled blue cheese (optional)
Toss well to coat. Serve immediately.