How to Make It
In a large saucepan, combine the wheat berries and onion with 3 1/2 cups of the stock and 1 teaspoon of salt; bring to a boil. Cover and simmer over moderately low heat until the wheat berries are tender but chewy, about 1 hour. Remove from the heat.
In a medium saucepan, combine the quinoa with 2 cups of the stock and 1/2 teaspoon of salt and bring to a boil. Cover and simmer over low heat until the quinoa is tender and most of the liquid has been absorbed, about 12 minutes. Remove the quinoa from the heat and stir. Cover and let stand for 5 minutes, then add to the wheat berries.
Stir the remaining 1/2 cup of stock into the grain mixture if it seems dry. Cover and cook over moderate heat, stirring occasionally, until warmed through, about 5 minutes. Stir in the parsley, season with salt and pepper and serve.