For the sauces, peel the garlic and press it through the garlic press. Mix into 4 tablespoons of mayonnaise and 2 tablespoons of yoghurt. Season to taste with salt and pepper. Mix the remaining mayonnaise, yoghurt and ketchup.
Season to taste with brandy, salt and cayenne pepper. Peel and finely chop the onion. Wash and chop the herbs. Mix vinegar with onions, herbs and breadcrumbs. Season with salt and pepper. Whip oil into it.
For the crab stock, bring wine, mustard seeds and bay leaves to the boil. Wash the dill, pluck the pennants and add to the stock. Leave the crayfish to soak for about 5 minutes. Cut corn into thick wheels and fry briefly in a pan with hot fat.
Wash the lemon hot and put it on skewers with the corn wheels. Serve with the crabs on a plate and add baguette.