Pat chicken thighs dry with paper towels and season with black pepper. Heat avocado oil in a large, heavy-bottomed pot or Dutch oven over medium-high heat.

Brown the chicken thighs skin-side down first, about 4-5 minutes per side until golden brown. Work in batches if necessary to avoid overcrowding. Remove chicken and set aside.

In the same pot, add minced garlic and sauté for 30 seconds until fragrant. Add soy sauce, apple cider vinegar, brown sugar, bay leaves, and water. Stir to combine.

Return chicken to the pot, nestling pieces into the sauce. Bring to a boil, then reduce heat to low and cover. Simmer for 30-35 minutes until chicken is tender and sauce has reduced.

Remove the lid and increase heat to medium. Continue cooking for 8-10 minutes, turning chicken occasionally, until sauce thickens and becomes glossy.

Remove bay leaves before serving. Taste and adjust seasoning if needed. Garnish with sliced green onions and serve over steamed rice or with vegetables.