Preheat oveb to 425
In a large heavy skillet, heat the oil over medium-low heat, Add the onions and whole garlic cloves and cook, stirring often, until they soften and are light golden all t he way through, about 20 min. Add the jam and red pepper flakes and stir until the jam is melted, about 30 seconds. Season with salt and pepper (season it on the light side because it's going to concentrate in the oven).
Transfer to a 9 x 13-inch baking dish (line it with foil for easy cleanup). Season the drumsticks generously with salt and papper, dump them on top of the onion-jam mixture, and spoon the onion stuff on top of the chicken to coat it. Bake until the mixture is bubbling, the chicken is cooked through with crisp skin, and the onions and garlic have darkened, 35 to 40 min, basting the chicken with the sauce every 15 min or so. If you want more color, crank the broiler on low and broil the chicken until the souce bubbles and onions darken, 1 to 2 min, but be careful not to burn it. Taste the sauce, season it with salt and pepper if necessary, and serve the drumsticks with the sauce drizzled on top.
