Pork Tofu and Watercress Soup

Ingredients

• 2 teaspoon vegetable oil
• 1/2 pound pork belly, sliced thinly
• 16 ounce firm tofu, cut into 1/2" dice
• 2 cloves garlic, finely minced
• 1 teaspoon ginger, finely minced
• 1 pound watercress, thick stems removed, cut into 1"-2" pieces
• 4 cup low-sodium chicken broth
• 1 tablespoon sesame oil
• salt and pepper, to taste