How to Make It
Preheat the oven to 350°. In a medium enameled cast-iron casserole, heat 1 tablespoon of the olive oil. Add the rice and cook over moderately high heat, stirring, until lightly toasted and well coated with oil, about 3 minutes. Add the mushroom broth and soy sauce and bring to a boil. Cover and cook over very low heat until the rice is tender and all of the liquid has been absorbed, about 20 minutes.
Meanwhile, in a large skillet, heat the remaining 1 tablespoon of olive oil. Add the mushrooms, season with salt and pepper and cook over moderately high heat, stirring occasionally, until lightly browned and tender, about 8 minutes. Transfer the mushrooms to a plate.
Add the merguez to the skillet and cook over moderately high heat, breaking up the sausage with a spoon, until cooked through and lightly browned in spots, 8 to 10 minutes. Return the mushrooms to the skillet and cook for 1 minute. Stir the merguez and mushrooms into the rice.
Bake the rice, covered, in the middle of the oven for 30 minutes. Remove the casserole from the oven and let stand for about 10 minutes; don't remove the lid. Fluff the rice with a spoon and serve.