how ong does it take for a large beetroot to cook
1 Add salt and sugar then cover (approximately 1 tsp sugar + 1 tsp salt per 1/2 gallon of water). 2  Turn heat on high until water begins to boil then reduce heat to medium to keep water at a simmer. 3  Cook 45 minutes to an hour or until done (for large, fresh ones) or up to four hours (for large, older ones from storage).irections: 1  Arrange pieces on a baking sheet then drizzle with about 2 tablespoons of vegetable oil (or about 1 tablespoon oil per pound). 2  Season generously with salt and pepper then toss them until coated. 3  Cook in oven for about 45 minutes or until they are tender right through, turning them at least once.