Brown the lamb in a large pot over medium heat until the pieces develop color on all sides. Remove the lamb and set it aside.

Add the onions and carrots to the same pot. Cook them for a few minutes until the onions turn soft.

Return the lamb to the pot along with the broth and thyme sprigs. Bring everything to a simmer, then cover and cook for 45 minutes.

Stir in the potatoes and turnips. Continue simmering uncovered for another 30 minutes until the vegetables are tender and the broth thickens slightly.

While the stew finishes, melt the butter in a skillet over medium heat. Add the sliced cabbage and cook it for 5 to 7 minutes, stirring often, until it softens but still holds some bite. Season with salt and pepper.

Remove the thyme sprigs from the stew. Stir in the chopped parsley and adjust salt and pepper as needed. Serve the stew in bowls with a portion of buttered cabbage on the side.