Preheat oven to 425°F (220°C). Line a large sheet pan with aluminum foil for easy cleanup. This takes about 15 minutes.

Pat 6 bone-in, skin-on chicken thighs completely dry with paper towels, pressing gently on both sides. Moisture prevents crispy skin, so don't skip this step (this takes 3 to 5 minutes).

In a small bowl, whisk together 2 teaspoons kosher salt, 1 teaspoon black pepper, 1 teaspoon garlic powder, 1 teaspoon onion powder, 1 teaspoon paprika, 1/2 teaspoon dried thyme, 1/2 teaspoon dried rosemary, and 1/4 teaspoon cayenne pepper. Set the spice blend aside (this takes 2 minutes).

Brush all sides of each chicken thigh with 3 tablespoons olive oil using a pastry brush or your hands, making sure every surface is lightly coated (this takes 2 to 3 minutes).

Sprinkle the spice blend evenly over both sides of each chicken thigh, rubbing it in gently with your fingers so it adheres. Season generously—don't be shy (this takes 3 to 4 minutes).

Arrange the seasoned chicken thighs skin-side up on the prepared sheet pan, spacing them about 2 inches apart so hot air circulates and skin crisps evenly.

Around the chicken (not on top of it), scatter 4 smashed garlic cloves, 2 lemon halves, 1 medium yellow onion cut into 6 wedges, 2 cups baby potatoes halved, and 1 cup baby carrots.

Pour 1/2 cup low-sodium chicken broth into the bottom of the pan around the vegetables and chicken. The broth keeps vegetables moist and creates pan drippings (this takes 1 minute).

Place the sheet pan on the middle oven rack. Roast at 425°F for 35 to 40 minutes. After 20 minutes, rotate the pan 180 degrees for even browning (roasting time total: 35 to 40 minutes).

At 35 minutes, check for doneness: the chicken skin should be deep golden brown and crispy-looking, and the meat should no longer be pink. Use an instant-read meat thermometer inserted into the thickest part of a thigh without touching bone—it should read 165°F (74°C) internally.

Checkpoint: You are ready to move on when the skin is deep golden brown, the thighs are no longer jiggly, and the internal temperature reaches 165°F.

Remove the sheet pan from the oven carefully—the pan is extremely hot. Let the chicken rest on the pan for 5 minutes before serving. This allows juices to redistribute through the meat, keeping it tender (resting time: 5 minutes).

Garnish the finished dish with 2 tablespoons fresh chopped parsley scattered over the chicken and vegetables. Serve directly from the sheet pan for a casual presentation, or transfer to a serving platter.

Drizzle pan juices over the chicken and vegetables just before serving. These flavorful drippings add moisture and depth (optional but recommended).