Step 1

Place beef in a large bowl. Add flour. Season with salt and pepper. Toss to coat.

Step 2

Heat the oil in a 10-cup-capacity, heavy-based flameproof casserole dish over medium-high heat. Cook beef, in 3 batches, for 5 to 6 minutes or until browned all over. Transfer to a heatproof bowl.

Step 3

Add onion to dish. Cook, stirring occasionally, for 5 minutes or until softened. Add garlic and paprika. Cook for 1 minute. Stir in tomato paste, mustard and stock. Bring to the boil. Return beef to dish. Reduce heat to low. Cover. Simmer, stirring occasionally, for 11⁄2 hours. Remove lid. Simmer for a further 1 hour (see notes). Add mushrooms. Season with salt and pepper. Simmer, uncovered, stirring occasionally for 30 minutes or until beef is very tender. Remove from heat (see notes). Stir in sour cream.

Step 4

Preheat oven to 200C/180C fan-forced.

Step 5

Meanwhile make Mash Topping: Place potato in a large saucepan. Cover with cold water. Bring to the boil over high heat. Boil for 12 to 15 minutes or until potato is very tender. Drain well. Return potato to pan. Add sour cream and half of the butter. Mash until smooth and combined. Season with salt and pepper.

Step 6

Dollop beef mixture with mash topping. Spread to cover filling. Dot with remaining butter. Bake for 25 minutes or until top is golden. Stand for 10 minutes. Sprinkle with chives. Serve with beans.