Buffalo Chicken Drumsticks with Celery Salad

Preheat oven to 450 degrees F. Line a rimmed sheet pan with parchment paper. Rinse chicken and pat dry thoroughly. Drizzle with olive oil; season with salt and pepper. Arrange chicken in a single layer and bake for 25 minutes. Meanwhile, in a medium mixing bowl add apple cider vinegar, 2 tablespoons olive oil, Dijon, 1/2 teaspoon salt, and 1/4 teaspoon black pepper. Whisk together and toss dressing with celery, red onion, and parsley. Keep in refrigerator until ready to serve. After roasting chicken for 25 minutes, heat broiler and cook chicken for 5 minutes more, watching carefully to avoid burning. Meanwhile, in a large pot over medium heat add butter, hot sauce, blue cheese, and 1/2 teaspoon salt; whisk until butter and cheese are melted. Reserve half of the sauce for garnish. Toss chicken in the pot with remaining buffalo sauce. Toss celery salad and transfer to a platter. Place buffalo chicken on top of salad. Top with reserved buffalo sauce, blue cheese, and parsley.