Place beef, breadcrumbs, onion, garlic, thyme, barbecue sauce, Worcestershire sauce and egg in a large bowl. Season and mix well. Use your hands to shape into 12 patties. Place on a tray. Cover and place in the fridge for 30 minutes to chill and firm up.
In batches, spray the rissoles and air fryer basket with oil. Cook at 180°C for 10 minutes or until golden and cooked through.
Meanwhile, to make the stroganoff sauce, heat the oil in a large frying pan over medium-high heat. Cook mushroom and onion, stirring, for 4-5 minutes or until lightly golden. Add flour, tomato paste and paprika. Cook, stirring, for 1 minute or until combined. Add stock and Worcestershire sauce, and stir until well combined. Bring to the boil. Reduce heat to medium and simmer, stirring occasionally, for 2-3 minutes or until thickened slightly. Remove pan from the heat and stir in the sour cream.
Serve the rissoles with mashed potato and steamed broccolini, topped with stroganoff sauce.
