Blend the peppercorns, cumin, cloves, garlic, and onion in a blender. Marinate the chicken legs for one hour. Place the chicken legs in a baking dish.

Season both sides with salt and pepper and set aside.

In a bowl, mix the two types of mustard with the orange juice.

Dip each chicken leg into the mixture.

In a baking dish, arrange sliced onions and potatoes, and place the chicken legs on top.

Once arranged, pour the remaining mustard mixture over the top, cover with aluminum foil, and bake in the oven for one hour.