4 medium yellow onions, halved and thinly sliced
4 medium garlic cloves, smashed and peeled
1 (5-inch) piece fresh ginger, cut into 1-inch pieces
1 bay leaf
3 pounds bone-in, skin-on chicken thighs
3/4 cup soy sauce
1/4 cup rice vinegar
1 tablespoon granulated sugar
1/2 teaspoon freshly ground black pepper
Steamed rice, for serving