Combine all of the vinaigrette ingredients in a small bowl and whisk well. Heat a grill over medium high heat, place the cheese slices directly on the grill, cook for 5 minutes or until the bottom is well marked and nicely browned. Carefully flip over with a metal spatula and cook for another 5 minutes. Remove from the heat. Toss the greens with about 2-3 tablespoons of the dressing, reserve the remaining dressing for another use. Layer half of the baguette with the cheese, apple slices, and greens. Top with other half of bread and cut into 4 portions.
Serve immediately or wrap it up and stash in your picnic basket!