Add some vegetable oil to a large stockpot. Cut sausages add to stockpot and cook over medium-heat stirring and flipping occasionally until lightly browned. Transfer the sausages to a separate plate, and set aside.
Add the vegetable, leeks, carrots and celery and stir to combine. Saute for several minutes, stirring occasionally. Then add the cabbage and garlic, and saute for some more minutes, stirring occasionally.

Add the stock, potatoes, Italian seasoning, bay leaf, cooked sausage, pepper, salt and stir to combine. Simmer until the potatoes are cooked and tender.

Step by step video https://youtu.be/D_aBnuK5djY?sub_confirmation=1