Skin the kidneys, remove the cores and soak in cold water for 5 min. Chop the kidneys and bacon. Fry the bacon until crisp and keep hot. Fry the chopped mushrooms and kidney for 5 min. in the bacon fat. Halve and grill the tomatoes and season carefully with salt and pepper. Poach the eggs. Fry croûtes of bread in the fat until golden on both sides, and keep hot in the oven. Reheat the bacon in the fat and add the kidneys and mushrooms. Correct the seasoning and spread equally on the croûtes. Place an egg on each one and dredge with paprika pepper. Garnish each with ½ tomato. Serve at once.