Place the chicken in a gallon-size resealable plastic bag.
Combine the onion, 6 garlic cloves, 2 tablespoons chopped fresh ginger, serrano pepper, and oil in a blender, and process on high speed until it forms a smooth paste. Add the paprika, 1 1/2 teaspoons salt, cumin, turmeric, coriander, garam masala, and cayenne, and continue to process until well blended. Add 1 /2 cup yogurt and 1 tablespoon lemon juice, and process again to form a smooth sauce, scraping down the sides of the bowl as necessary. Pour the marinade over the chicken, seal the bag, and refrigerate for at least 4 hours and up to 24 hours, turning the chicken occasionally.
Preheat the oven to 500 degrees F. Line a large rimmed baking sheet with parchment paper.
Remove the chicken from the marinade, pat it dry with paper towels, and arrange in one layer on the baking sheet. Brush the chicken on one side with just enough vegetable oil to coat and season it with the kosher salt and 1 /4 teaspoon white pepper. Place the chicken in the oven and cook for 15 minutes. Turn the chicken pieces on the other side and continue to cook 5 to 10 minutes longer until nicely browned and cooked through and an instant- read thermometer inserted into the thickest part of the drumstick (without touching the bone) registers 160 degrees to 165 degrees F. Remove the chicken from the oven and let it rest briefly.
While the chicken is cooking, make the yogurt dipping sauce by combining the remaining 1 cup yogurt, mint, honey, minced garlic, the remaining 1 1 /2 teaspoons ginger, 1 1/2 tablespoons lemon juice, 34 teaspoon salt, and remaining 1 /2 teaspoon white pepper in a bowl and stirring until well incorporated. Serve with the chicken.