Preheat oven 350℉.: When the oven warms, you will feel a dry, steady heat in the kitchen that primes the air for roasting. A properly preheated oven ensures even browning across the chicken skin and helps the garlic cloves roast gently until they are jammy. If you skip preheating, the skin may cook unevenly and fail to crisp. A quick check is to use an oven thermometer to confirm the temperature is accurate.
Chop off the top 1/2 inch of the whole garlic heads.: After you cut the tops, the cloves peek out, allowing oil and heat to penetrate during roasting. You will notice an immediate burst of raw garlic aroma that will mellow as it cooks. Doing this step wrong, such as cutting too deep, can cause loose pieces to scatter and burn, so remove just enough to expose the cloves.
Add chicken legs, whole garlic heads, and the 40 peeled garlic cloves to a 9×13-inch baking dish.: As you arrange the pieces, the visual contrast of pale cloves and skin on chicken is striking. Make sure the pieces are spaced so air can circulate and the surface can brown. Overcrowding will steam the meat instead of roasting it, resulting in limp skin and less flavorful garlic.
Add the olive oil, orange juice, thyme, dry rosemary, salt, pepper, and honey to a small bowl.: Mixing these creates a unified glaze that will coat the chicken and cloves. As you whisk, the fragrance shifts from citrusy to herby, and the honey emulsifies into the oil. If you fail to combine the ingredients properly, the seasoning may pool instead of adhering, leading to uneven flavor.
Mix with a fork then drizzle the mixture over the chicken and garlic.: The act of drizzling lets the glaze settle into crevices, scenting the chicken and garlic. You should see a glossy sheen form on the skin which helps with caramelization. A common pitfall is to pour too much in one spot, which can create soggy areas, so aim for even coverage.
Bake for 35-40 minutes, or until the chicken is golden brown and cooked through (165℉ internally).: In the oven you will hear faint sizzling, and the aroma will deepen into toasty, citrusy notes. Watch for a rich, golden color on the skin and a thermometer reading of 165℉ at the thickest part near the bone. If you remove the dish too early, the juices will not have set and the texture will be gummy; if you overcook, the meat will dry out. Rotate the pan halfway if your oven has hot spots for consistent browning.
Serve with fresh rosemary stems and enjoy!: When you lift the dish, the steam carries concentrated scents of roasted garlic and herbs. The tender cloves should be soft enough to spread, and the chicken skin should crackle under a fork. Let the dish rest briefly so juices redistribute, then garnish with rosemary for a fragrant finish. A mistake here is carving immediately, which can release juices and make the meat less moist.