Preheat the oven to 425ºF (220ºC).
Bring about 2 quarts (2l) of well-salted water to a boil, then add the wheat berries and bay leaf. Cook until tender, but still chewy. Depending on the variety, they’ll take between 40-60 minutes to cook.
While the wheat berries are cooking, toss the diced vegetables on a baking sheet with the onion and 2 tablespoons of olive oil and thyme, seasoning with salt and pepper.
Roast the vegetables in the bottom third of the oven, stirring once midway during baking, for 20 minutes, or until cooked through and browned on the outside.
Once the wheat berries are cooked, drain them well, plucking out the bay leaf. Transfer the wheat berries to a bowl and mix in 1/3 cup (80 ml) of olive oil and the dried fruits, stirring well. Taste, seasoning with more salt if necessary
Stir in the root vegetables (I don’t mind the thyme branches in there, but you can remove them if you want) and do a final check for seasoning and add more salt, a few grinds of black pepper, and additional olive oil, if desired. You might want a splash of acid, like some vinegar in there, or check some of the additions below.