Heat olive oil and butter over medium heat. Sauté onion and celery slowly for about 10 minutes, until translucent.
Add mushrooms and increase heat. Sauté for another 10 minutes or so until softened and caramelized. Season with salt and pepper.
Add half of the sage and thyme. Stir in brown rice and season with salt and pepper.
Add stock and bring to a boil. Boil for 15-20 minutes, until liquid is absorbed. Fluff rice with a fork and stir in cranberries, remaining herbs, and slivered almonds.