Heat vegetable oil in a large pot over medium heat. Add the diced onion and sauté until translucent, about 5 minutes.
Add the maral meat cubes to the pot, cooking until browned on all sides, around 8-10 minutes.
Stir in the minced garlic and sliced carrots, cooking for an additional 3-4 minutes until the carrots soften slightly.
Pour in the beef or vegetable broth and bring to a boil. Once boiling, reduce heat to a simmer.
Add the chopped fern fronds, cubed potatoes, dried thyme, black pepper, and salt. Stir well to combine.
Cover the pot and let the stew simmer for about 45 minutes, stirring occasionally, until the meat is tender and flavors meld together.
Taste and adjust the seasoning if necessary. Remove from heat and let it sit for a few minutes before serving.
Garnish with fresh parsley if desired and serve hot.