Preheat the oven to 200°C | 390°F. Place the turkey breast in a large roasting pan lined with parchment paper, skin side up. Pierce through the skin and flesh with a fork, all over the breast. Set aside.
In a small bowl, combine 4 tablespoons olive oil, garlic, parsley, thyme, paprika, salt, and pepper. Rub HALF of the mixture evenly all over the skin of the turkey breast. Loosen the skin and rub the seasoning underneath the skin and onto the meat. Pour the {extra} 2 tablespoons oil underneath the turkey breast onto the parchment paper. Turn the breast over, skin-side down.
Arrange the sweet potatoes and potatoes around the turkey, and rub them with remaining seasoning. Season with extra salt, if desired.
Cover pan completely with aluminium foil. Roast for 2 hours.
Remove from oven, carefully uncover the turkey, and turn in the pan to be skin-side up. Change oven setting to grill or broil, and continue to roast the turkey for a further 30 minutes - 45 minutes, or until the skin is crispy and the turkey is completely cooked through.
When the turkey is done, remove from the oven, cover the pan with the same foil, and allow to rest at room temperature for 15 minutes. Slice and serve warm with the gravy.