INGREDIENTS
1 cup
Baby arugula
1/2 tsp
Thyme, fresh
2
Yellow onions, medium large
2 tbsp
Dijon mustard, smooth
1/3 cup
Mayonnaise
1 tbsp
Mustard, whole-grain
1
Black pepper, Freshly ground
2
Kosher salt
1
Olive oil
2
Large or 4 medium (about 6″) focaccia or ciabatta buns
2 tbsp
Sour cream
1
1-inch thick new york strip boneless beef top loin or hangar steak