Boil the mussels and subtract nuts shells. Half sunflower oil stew consistently chopped onion, garlic, carrots and celery into small cubes. Add remaining sunflower oil and 1/3 cup water, continue to stew over medium heat until vegetables are soft. Put flour (previously toasted in a dry pan and mixed into 1/3 cup lukewarm water), mussels, pepper, bay leaf, salt to taste and keep the court after the fire for 10 minutes, transfer the mixture into a baking dish. Top arrange sliced ​​tomatoes and slices of peeled lemon. Bake in a moderate oven until the fat remains. Serve cold plates.