Begin by carefully trimming the beef to remove any veins, then cut it into uniform 3 × 3 cm cubes to ensure even cooking. Marinate the meat thoroughly with mustard and an aromatic blend of spices, then cover and refrigerate for one hour to allow the flavors to penetrate deeply. Next, heat a tablespoon of pork fat or vegetable oil in a large, heavy-bottomed pot over medium heat. Brown the marinated beef pieces on all sides, creating a caramelized exterior that locks in juices and adds rich color. Once evenly browned, transfer the meat to a plate, and add another tablespoon of fat to the pot to prepare for the vegetables. Finely chop the onions for a delicate texture and peel the carrots, grate them coarsely to release their sweetness. Cook these vegetables gently over low heat for approximately 15 minutes, seasoning lightly with salt to accelerate softening and develop sweetness; they should become tender and slightly golden. Once the vegetables have mellowed and are somewhat mushy, return the browned meat to the pot along with the fragrant bay leaves and crushed garlic cloves. Pour in the robust red wine, allowing it to simmer for 10-15 minutes so the alcohol evaporates while infusing the stew with deep flavor. At this stage, add two-thirds of the total liquid—water or stock—to create a hearty broth. Cover the pot and let the stew slowly simmer over low heat for one hour, stirring occasionally to prevent sticking and encourage even cooking. After this initial period, add the remaining liquid to maintain the stew’s consistency, and continue cooking gently for another 30 to 45 minutes until the meat is tender and the flavors harmonize. Allow the goulash to cool slightly before serving, then garnish generously with freshly chopped parsley for a burst of color and freshness. Add a few slices of fresh hot pepper if you desire a subtle kick to enliven the dish. For the best experience, serve this comforting stew alongside slices of fresh rustic bread and a simple seasoned salad. The bread is perfect for dipping into the luscious sauce, completing a satisfying traditional Croatian meal.