Heat the oven to 220C/200C fan/gas 7 and oil a baking tray. Combine the beef mince, egg, 1 tbsp flour and a pinch each of salt and ground black pepper in a large bowl. Scoop as many meatballs as you can out onto the tray using an ice-cream scoop, then bake for 10-12 mins until the meatballs are evenly browned.

Meanwhile, make the sauce. Heat the garlic oil in a small pan over a medium heat and cook the mushrooms for a few minutes until slightly golden. Stir in the remaining flour, the paprika, mustard and tomato purée, then mix to coat the mushrooms. Pour in the stock, season, then simmer for a 5-6 mins until slightly thickened. Reduce the heat to low and stir in the soured cream. Cook for 1 min more, then add the meatballs and stir to coat in the sauce. Once completely cool, will keep frozen for up to three months. Defrost overnight in the fridge, then reheat until piping hot. Serve the meatballs and sauce with mash and wilted spinach.