Buffalo Cambozola burger

Ingredients

• 2 pounds ground buffalo
• 2 teaspoons kosher salt
• 1/4 teaspoon fresh ground pepper
• 4 tablespoons olive oil, divided
• 3 large onions, thinly sliced across the grain
• Chopped leaves from 3 sprigs fresh rosemary
• 3 crushed cloves garlic
• 1/2 cup medjool dates, pitted
• 2 to 3 dried black mission figs
• 1/2 cup water
• 1 tablespoon balsamic cream
• 6 ounces Cambozola cheese
• 6 kaiser hamburger buns
• 1 1/2 cups watercress or arugula leaves