Bistro Burger

Directions

1. 1
   Whisk together the vinegar and mustard in a medium bowl and season with salt and pepper.
2. 2
   Slowly add the olive oil and whisk until emulsified.
3. 3
   Add the endive to the bowl and toss to coat.
4. 4
   Let sit at room temperature for 15 minutes before serving.
5. 5
   Divide the meat into 4 equal portions (about 6 ounces each).
6. 6
   Form each portion loosely into a 3/4-inch-thick burger and make a deep depression in the center with your thumb.
7. 7
   Season both sides of each burger with salt and with the coarsely ground black pepper.
8. 8
   Cook the burgers, using the oil (see page 16) and topping each one with a slice of cheese and a basting cover during the last minute of cooking (see page 21).
9. 9
   Place the burgers on the bun bottoms and top each one with some of the endive.
10. 10
    Cover with the bun tops and serve immediately.