Preheat oven at 210°C/410°F. Put olive oil, butter, lemon juice, salt and pepper, thyme and any other seasoning of your choosing into a deep baking dish. Mix well and place the chicken pieces on top, then the potatoes cut into big cubes and toss to coat. Add lemon slices and adjust the seasoning.
Cover with tinfoil and roast for about 50 minutes or until the potatoes are tender. Remove tinfoil and put back into the oven for another 5-10 minutes until golden brown.