Heat a large pot over medium heat, then add the olive oil. Add the onion and cook until translucent, about three to four minutes. Add the rosemary, sage, and salt, and cook until fragrant, about one minute.
Add the wild rice and brown rice, and stir until the grains are evenly coated in oil. Cook until the rice is lightly toasted, about two to three minutes.
Add the broth and bring the mixture to a boil. Reduce the heat to low, cover, and cook until the rice is tender and the moisture has been absorbed, about 50 to 60 minutes.
Once the rice is cooked, fluff with a fork, add the dried cranberries, and toss until combined. Enjoy warm.
Make Ahead: Prepare this dish up to three days in advance. Reheat at 300 degrees F for 25 to 30 minutes in a casserole dish covered with foil.