Saute onion in olive oil until golden. 

Place chicken pieces on top of onions and season with salt and pepper. 

Add orange juice to pot and cover chicken in orange slices. If you use peels on Pesach, you can also add some orange zest to the pot to intensify the flavors. 

Bring orange juice up to a boil, lower flame and simmer for 45 minutes. Uncover the pot and cook over high heat until liquid is thickened and reduced by half, about 15 minutes. 

Serve over mashed potatoes or sweet potatoes to sop up all the delicious orange-onion sauce!