Preheat the oven to 400 degrees F.
Poke holes in the sweet potato halves with a fork. Place on a parchment- or foil-lined baking sheet and bake until fork tender, about 1 hour. Alternatively, microwave on high until the flesh is fork tender, 6 to 8 minutes. Set aside.
Tie the sage, thyme and rosemary sprigs together with kitchen twine or a clean rubber band and set aside.
Heat a Dutch oven over medium heat and cook the bacon, stirring often, until crisp, about 10 minutes. Use a slotted spoon to transfer the bacon to a paper-towel-lined plate and discard all but 1 tablespoon of the pan drippings.
Pat the beef dry and sprinkle with salt and pepper. Return the Dutch oven to the stovetop on medium-high heat. Working in batches, brown the meat on all sides, 5 to 7 minutes. Add the broth, onions, carrots, celery, tomato paste, garlic and herb bundle. Bring to a boil, then reduce to a simmer. Cover and cook for 1 hour on low heat.
Uncover and cook at a low simmer until the meat is tender and the vegetables are cooked through, 45 minutes.
Scoop out the flesh from the cooked sweet potatoes and place in a blender. Carefully add 1 cup of the stewing liquid and the cashew butter to the blender, then puree until smooth. Add the puree to the stew and stir well. Simmer to thicken, 5 minutes, then season with salt and pepper. Remove the herb bundle and serve the stew garnished with the bacon bits and parsley leaves.
When blending hot liquid, first let it cool for five minutes or so, then transfer it to a blender, filling only halfway. Put the lid on, leaving one corner open. Cover the lid with a kitchen towel to catch splatters, and pulse until smooth.
(c) 2014 Turner Broadcasting System, Inc. All rights reserved.