1. Rinse and drain the chicken, then transfer to a large bowl or container. Add the milk and toss to coat. Arrange the chicken in an even layer, making sure all the chicken is submerged in the milk. Cover and refrigerate for 1 hour.

2. Drain and thoroughly rinse the chicken until the water runs clear. Clean and dry the bowl. Using a sharp knife, make 4 to 6 slashes in each drumstick (each slash should reach the bone). Pat the chicken dry with paper towels and transfer to the bowl.

3. Add the oil, ½ tsp salt, and ½ tsp pepper and toss the chicken to coat. Cover and refrigerate for at least 1 hour or up to overnight.

4. Whisk the honey, soy sauce, vinegar, sugar, remaining 1/2 tsp salt, and remaining ½ tsp pepper together in a small bowl; set the sauce aside.

5. Toss the chicken again to coat in the oil that has settled in the bowl. Working with 1 drumstick at a time, stretch the skin to evenly cover the meat, then arrange skin side down in a 12 in [30.5 cm] nonstick skillet. Drizzle any remaining oil left in the bowl over the chicken. Cook over medium-high heat, turning the chicken occasionally, until spotty golden brown, about 10 minutes.

6. Reduce the heat to medium, cover, and continue to cook, turning the chicken occasionally, until it registers at least 185F [85C], about 20 minutes.

7. Spoon the garlic into the spaces between the drumsticks where the oil has pooled. Cook, spreading the garlic into the skillet with the back of a spoon, until fragrant, about 30 seconds. Gently toss the chicken until evenly coated with the garlic. Add the sauce, stirring in any browned bits in the skillet. Increase the heat to medium-high and cook, continuously coating and basting the chicken in the sauce, until the sauce has thickened, about 2 minutes. Stir in the butter until the sauce has thickened into a glaze, about 30 seconds. Serve.