Bistro Burger

Directions

1. 1
   In a bowl, whisk the vinegar and mustard together; season with salt and pepper to taste.
2. 2
   Slowly add the olive oil and whisk until emulsified.
3. 3
   Add the endive to the bowl and toss to coat; let sit at room temperature for 15 minutes before serving.
4. 4
   Divide the meat into 4 equal portions (about 6 ounces each); form each portion loosely into a 3/4 inch thick burger and make a deep depression in the center with your thumb.
5. 5
   Season both sides of each burger with salt and pepper.
6. 6
   Heat oil in a pan or griddle over high heat until the oil begins to shimmer; cook the burgers until golden brown and slightly charred on the first side, about 3 minutes for beef, 5 minutes for turkey; flip burgers over; cook until golden brown and slightly charred on the second side (4 minutes for med-rare beef, 5 minutes for turkey).
7. 7
   During last minute of cooking, cover each patty with a slice of cheese and cover with a basting cover or tent burgers with foil.
8. 8
   Place burgers on the bun bottoms and top each one with some of the endive.
9. 9
   Cover with the bun tops and serve immediately.