Season the beef with paprika, garlic powder, onion powder, salt & pepper.
Heat a large skillet on high. Add a pad of butter and brown meat in batches. Set aside.
Add pad of butter and crimini mushrooms to pan. Cook 4-5 minutes until browned. Set aside.
Reduce heat to medium. Add pad of butter and onions. Sprinkle some salt and sauté for 4-5 minutes until translucent. Add garlic and cook through.
Add tomato paste and Dijon mustard. Mix well and warm through. Set aside.
Deglaze pan with white wine and reduce by half.
Combine all the ingredients previously set aside back into the pan. Add beef broth and nutmeg then bring to a boil. Reduce heat to a low simmer.
Cook for 4-5 hours until meat is tender.
20 minutes before serving, add sour cream and lemon. An additional pad of butter is also recommended to give a nice shine to the sauce (and what's a little more butter?). Season with additional salt if necessary. Garnish with some chopped parsley and serve.