Heat the olive oil in a large skillet over medium heat. Add the beef stew meat and brown on all sides for about 5 minutes.
Transfer the browned beef to the slow cooker. Add the onion, carrots, celery, garlic, butternut squash, Brussels sprouts, diced tomatoes, beef broth, thyme, rosemary, salt, and pepper.
Stir everything to combine, then cover and cook on low for 7 to 8 hours.
Stir in the chopped kale during the last 30 minutes of cooking so it wilts without turning mushy.
Taste and adjust salt and pepper before serving.
Notes
Add the kale only at the end to keep its color and texture. If the broth needs more body, mash a few pieces of squash against the side of the pot before serving. Leftovers reheat well on the stovetop with a splash of broth to loosen the vegetables.Course: Main Course
Cuisine: American
Equipment: Slow Cooker, Large Skillet