» Grilled Flank Steak with Grapes and Stilton

Ingredients

• 1 flank steak (2 pounds)
• Kosher salt and freshly ground black pepper
• 1 1/2 tablespoons red wine vinegar
• 1 tablespoon chopped shallot
• 1/4 teaspoon Dijon mustard
• 1/4 cup extra-virgin olive oil
• 2 bunches watercress, trimmed (8 cups)
• 1/2 cup crumbled Stilton or other blue cheese
• 2 cups red California grapes, halved