Heat 1 tablespoon olive oil in a large skillet over medium-high heat for 2 minutes until shimmering. Pat 3 pounds chicken breasts dry with paper towels. Sprinkle lightly with salt and pepper. Place chicken in the hot skillet and sear for 2–3 minutes per side until the outside is golden brown (you should see a caramelized crust). This adds depth of flavor, but can be skipped if you're in a hurry. Checkpoint: Chicken should be golden on both sides, not cooked through.

Transfer the seared chicken breasts to a 6–7 quart slow cooker. Place 1 medium yellow onion (quartered into 4 large chunks) and 4 minced garlic cloves around the chicken.

In a small mixing bowl, whisk together: 1 cup chicken broth, 1/2 cup apple cider vinegar, 2 tablespoons honey, 1 tablespoon Dijon mustard, 1 teaspoon smoked paprika, 1 teaspoon dried thyme, 1/2 teaspoon dried oregano, 1/2 teaspoon ground cumin, 1/2 teaspoon black pepper, 1 teaspoon sea salt, and 2 bay leaves. Whisk for 30 seconds until honey and mustard are fully combined. Checkpoint: The liquid should smell aromatic and savory with a touch of sweetness.

Pour the entire liquid mixture over the chicken breasts. The liquid should cover about 2/3 of the chicken.

Place the lid on the slow cooker. Cook on LOW for 6–7 hours (recommended for most kitchens) OR on HIGH for 3–4 hours. The chicken will reach a safe internal temperature of 165°F around the 4–5 hour mark on low, but extended cooking ensures maximum tenderness. Checkpoint: The chicken should be so tender that it breaks apart easily when pressed with a fork. If still slightly firm, cook for another 30–60 minutes.

Carefully transfer the cooked chicken breasts to a cutting board or large shallow bowl using tongs or a slotted spoon. Discard the bay leaves. Remove the onion quarters and discard (they've given their flavor to the broth).

Using two forks (one in each hand), hold the chicken steady with one fork and pull the other fork through the meat repeatedly, working in opposite directions. The chicken will naturally separate into tender, shredded pieces. Shred all chicken into bite-sized strands (about 1–2 inches long). Checkpoint: All chicken should be in tender, pulled-apart pieces with no large chunks remaining.

Return the shredded chicken to the slow cooker and gently stir with a wooden spoon to combine with the cooking liquid. Stir for 30 seconds until evenly coated. The shredded chicken is now ready to serve immediately or store in an airtight container.