White bean and fish gratin recipe
 Dr Rupy's easy fish gratin uses frozen fish and vegetables to keep costs down without compromising on flavour. Each serving provides 233 kcal, 17.5g protein, 18.6g carbohydrate (of which 5.9g sugars), 7.9g fat (of which 1.7g saturates), 8.5g fibre and 0.74g salt. In November 2023, this recipe was costed at an average of £1.29 per portion when checking prices at three UK supermarkets. The recipe is designed to be made in conjunction with a low-cost store-cupboard. 2 tbsp olive oil, plus extra for drizzling350g/12oz leek, roughly sliced300g/10½oz celeriac, cut into 1cm/½in cubes400g tin butter beans, drained and rinsed1 vegetable stock cube3 tbsp dried mixed herbs1 tbsp fennel seeds (optional)½ tbsp cornflour (or plain flour)400g/14oz frozen mixed vegetables300g/10½oz frozen white fish (thawed), cut into thick chunks50g/1¾oz day-old bread, crackers or mixed nuts, roughly blended into crumbssalt and freshly ground black pepper 2 tbsp olive oil, plus extra for drizzling 350g/12oz leek, roughly sliced 300g/10½oz celeriac, cut into 1cm/½in cubes 400g tin butter beans, drained and rinsed 1 vegetable stock cube 3 tbsp dried mixed herbs 1 tbsp fennel seeds (optional) ½ tbsp cornflour (or plain flour) 400g/14oz frozen mixed vegetables 300g/10½oz frozen white fish (thawed), cut into thick chunks 50g/1¾oz day-old bread, crackers or mixed nuts, roughly blended into crumbs salt and freshly ground black pepper Method Heat the oil in a large casserole over a medium heat and add the leek and celeriac. Season with salt and pepper, put the lid on and cook for 7–8 minutes until softened.Meanwhile, place half of the beans in a small blender with 300ml/10fl oz hot water.Add the vegetable stock cube and blitz. The mixture should be fairly loose. Add the mixed herbs, fennel seeds (if using) and blended bean mixture to the leek mixture and bring to a gentle simmer. Stir in the cornflour to thicken the mixture. Add the mixed vegetables, fish chunks and remaining beans and cover with a lid for another 5–8 minutes to cook through. At this point, preheat a grill to medium–high. Remove the lid of the casserole and scatter with the crumbs. Drizzle with olive oil, sprinkle with some salt and pop under the grill for 2–3 minutes until golden and bubbling. Remove from the heat and leave to stand for a few minutes before serving. Heat the oil in a large casserole over a medium heat and add the leek and celeriac. Season with salt and pepper, put the lid on and cook for 7–8 minutes until softened. Heat the oil in a large casserole over a medium heat and add the leek and celeriac. Season with salt and pepper, put the lid on and cook for 7–8 minutes until softened. Meanwhile, place half of the beans in a small blender with 300ml/10fl oz hot water. Meanwhile, place half of the beans in a small blender with 300ml/10fl oz hot water. Add the vegetable stock cube and blitz. The mixture should be fairly loose. Add the mixed herbs, fennel seeds (if using) and blended bean mixture to the leek mixture and bring to a gentle simmer. Stir in the cornflour to thicken the mixture. Add the vegetable stock cube and blitz. The mixture should be fairly loose. Add the mixed herbs, fennel seeds (if using) and blended bean mixture to the leek mixture and bring to a gentle simmer. Stir in the cornflour to thicken the mixture. Add the mixed vegetables, fish chunks and remaining beans and cover with a lid for another 5–8 minutes to cook through. At this point, preheat a grill to medium–high. Remove the lid of the casserole and scatter with the crumbs. Drizzle with olive oil, sprinkle with some salt and pop under the grill for 2–3 minutes until golden and bubbling. Remove from the heat and leave to stand for a few minutes before serving. Add the mixed vegetables, fish chunks and remaining beans and cover with a lid for another 5–8 minutes to cook through. At this point, preheat a grill to medium–high. Remove the lid of the casserole and scatter with the crumbs. Drizzle with olive oil, sprinkle with some salt and pop under the grill for 2–3 minutes until golden and bubbling. Remove from the heat and leave to stand for a few minutes before serving. Recipe tips You can swap out some of these ingredients if preferred. For celeriac, you can also use parsnip, sweet potato or turnip. For white fish, use prawns, tuna or more white beans to make it vegetarian. Instead of frozen mixed vegetables, use broad beans, peas or frozen green beans.