Prepare the ingredients: Cut the beef into 1-inch cubes, peel and cube the butternut squash, slice the carrots, chop the celery, dice the potatoes, and mince the garlic.
Sear the beef: In a large pot, heat olive oil over medium heat. Brown the beef cubes on all sides, working in batches if necessary. Once browned, remove the beef from the pot and set aside.
Sauté the vegetables: In the same pot, add the onions, carrots, and celery. Cook for about 5 minutes until the vegetables soften slightly. Add the garlic and cook for an additional minute.
Deglaze the pot: Pour in a little beef broth to deglaze the pot, scraping up any browned bits from the bottom. This will add flavor to the stew.
Combine ingredients: Return the beef to the pot, along with the potatoes, butternut squash, thyme, and bay leaves. Pour in the remaining beef broth and stir to combine.
Simmer the stew: Bring the mixture to a boil, then reduce the heat to low and cover the pot. Let the stew simmer for about 2 to 2.5 hours, or until the beef is tender and the vegetables are cooked through.
Season to taste: Taste the stew and adjust the seasoning with salt and pepper as needed.
Serve: Remove the bay leaves before serving. Ladle the stew into bowls and garnish with fresh herbs, if desired.