Prep ingredients. Chop fresh dill, cut onion halves in to quarters, chop celery stalks into 4 pieces, and quarter red potatoes.
Place salt, pepper, and dill in a small bowl and combine well. Run mixture all over the roast.
Place onion, celery, potatoes, water and vinegar in bottom of crock pot. Place roast on top veggies. Set on low for 8 hours.
Last 20 mins of cooking prepare gravy. Wipe down and slice mushrooms. In a large skillet heat oil over medium add mushroom and add salt and pepper. Cook until tender moisture releases from mushrooms. Add sour cream and turn heat to low. Let cook for 5 mins stirring occasionally.
Remove roast and serve with mushroom sauce along with veggies. Enjoy!!