Complex sentence: Food could be prepared by stewing, baking, boiling, grilling, frying or roasting and spices and herbs were added for flavor, though the former were expensive imports and therefore confined to the tables of the wealthy.
Split into simpler sentences: Food could be prepared by stewing, baking, boiling, grilling, frying, or roasting. Spices and herbs were added for flavor, though the former were expensive imports and therefore confined to the tables of the wealthy.