Pat the beef dry with paper towels and season with salt and pepper. Heat 2 tablespoons of olive oil in a large dutch oven or heavy-bottomed pan over medium-high heat. Add the beef and cook until browned on all sides, about 10-15 minutes.
Remove the beef from the dutch oven and place it in the slow-cooker. Add the onions, carrots, and celery to the now empty dutch oven and cook until tender, about 6-8 minutes. Add the garlic, rosemary, and thyme and cook for another 30 seconds. Pour in the wine and scrap up all the browned bits from the bottom of the pan (all the flavor!). Allow the wine to cook and reduce for 5 minutes.
Pour the wine/vegetable mixture over the beef in the slow-cooker. Add the porcicni mushrooms, bay leaves, and beef broth. Cook on low for 6-8 hours or on high for 3-4 hours.
After the roast is done cooking, remove the meat from the dutch oven and place it on a serving platter tented with foil. Remove and discard the rosemary sprigs, thyme sprigs, and bay leaves. Skim as much fat as you can off the surface of the remaining liquid. Pour the liquid, including all the vegetables, into a blender and blend until smooth. Slice or shred the meat and pour over the gravy. Serve, passing the remaining gravy. Enjoy!