Heat the olive oil in a large skillet over medium-high heat. Add the beef pieces and cook until browned on all sides, about 5 minutes total. Transfer the beef to the slow cooker.
Add the onion, carrots, garlic, butternut squash, tomato paste, sage, salt, and pepper to the slow cooker.
Pour the beef broth over the ingredients and stir gently to combine everything.
Cover and cook on low for 8 hours or until the beef is fork-tender and the squash is soft.
Taste and adjust salt or pepper if needed before serving.