Heat the olive oil in a large pot over medium-high heat.
Add the ground beef to the pot, breaking it up with a spoon, and cook until browned.
Stir in the diced onion, sliced carrots, and sliced celery, cooking for 5 minutes until the vegetables begin to soften.
Add the minced garlic, sea salt, black pepper, and dried thyme, stirring for 1 minute until fragrant.
Pour in the beef broth and tomato puree, stirring to combine and scraping any browned bits from the bottom of the pot.
Bring the soup to a boil, then reduce the heat to low and simmer for 15 minutes.
Stir in the chopped kale and cook for an additional 2-3 minutes until the greens are wilted and tender.
Ladle the hot soup into a bowl and serve immediately.