Place the oat groats in a saucepan, cover with 2 cups water and bring to a boil over high heat. Turn the heat to low, cover the pan and cook for about 35 minutes or until the groats are tender but still a bit chewy. If there is any remaining water, strain the groats to discard the water. Spoon the groats into a bowl. Cook the carrots for 3-5 minutes or until tender but still firm. Drain and add to the groats. Add the scallions, raisins and herb, if used and stir the ingredients to distribute them evenly. Pour in the olive oil and vinegar and season to taste with salt and pepper. Toss ingredients and let rest for 10- 15 minutes before serving.