Step 1 To prepare beef stew: season beef with salt and black pepper. Toss beef in flour. Step 2 Heat up oil in a pan and when it is hot, add 1 tbsp of butter and when butter is completely melted, add your beef and brown on both sides for 4-5 minutes. Remove beef and place into a plate. Add 1 tbsp of oil, onion and garlic and saute for 2-3 minutes. Add paprika, tomato paste and cook for 2-3 minutes, add carrot and celery and saute for an additional 1-2 minutes. Step 3 Add your meat stock, beef, black pepper, salt, Italian seasoning/ thyme, and Worcestershire sauce. Bring to a boil and then transfer into your slow cooker and cook for at least 6 hours. Before your 6 hours mark is up, taste for seasoning and adjust with salt if needed, add 1 tbsp of butter, stir, cover and leave to complete cooking time. Step 4 To make mashed potatoes: peel and cut potatoes into small chunks. Bring to a boil and cook until soft and potatoes starts to break or fall apart. Drain and put potatoes back into the same pot and put on low heat. Mash potatoes for a little bit to let some steam escape, this gives the potatoes some texture. Then add your butter and milk or heavy cream and mash until properly incorporated and smooth. Season with salt and pepper and then mash until all ingredients are properly combined. Step 5 Your food is ready!!! Serve mashed potatoes with beef stew and garnish with parsley.