Preheat the oven to 400F (205C) with the oven rack in the middle or top third position.
Wash and peel the potatoes and coarsely chop them into vertical quarters or 1-inch thick pieces. Place them on a kitchen towel to dry any excess moisture. This helps the seasoning stick better.
Trim the chicken pieces of any excess fat and pat dry with a paper towel. Generously season the chicken pieces with salt and place them in the baking dish, skin-side up.
In a large bowl, combine olive oil, salt, garlic, Italian seasoning, and lemon juice. Add the potatoes and onion pieces into the large bowl, and toss them around to coat. Transfer them into the baking dish, placing them in and around the chicken pieces.
Roast:
Place the baking dish in the preheated oven and roast for 30 minutes.
After 30 minutes, lower the oven temperature to 375F (190C). Continue cooking in the oven for another 15 to 20 minutes, until the potatoes are fork tender and the dark chicken pieces have reached 175F (80C).
Serve:
Serve the chicken and potatoes, and use a spoon to drizzle some of the juices from the pan on top of the potatoes.