Cheap and yummy, what more could you want? Get a big baking potato, lay it flat and slice off the top. Scoop out a hollow in the big piece (a melon baller really helps), season it, and drop in a cored lamb kidney. Put the top back on and bake it at about Gas Mark 5 for about an hour and a half.
The potato is crisp, the kidney is gently cooked and moist, and the juices have oozed through into the floury potato inside.
I served it with broad beans in a mustard cream dressing. Next time I might put a bit of butter and mustard in the potato underneath the kidney. It would be good with a bitter green salad, or breakfast things like baked beans or mushrooms. I'll have to make spare next time, it drove the cat beserk – worse than catnip.