If you are cooking your own crab, place the live crab in the freezer for 30 minutes prior to cooking. Meanwhile, fill a pan large enough to house the crab with water and add a good amount of salt. Bring to a rolling boil and then place the crab in and submerge. Cook for 10 minutes per kilo.
Once cooked, leave the crab to cool in the water. Once cool enough to handle, take it out of the water, remove the legs and crack the shell. Carefully pick out the all white crab meat and place in a metal bowl, covered in the fridge. Reserve the shells and brown crabmeat for the custard.
To make the custard add the crab shells, brown meat and four of the chopped tomatoes into an ovenproof dish. Drizzle over olive oil and roast at 180°C for 15 minutes, stirring occasionally until the shells are brown and the tomatoes are broken down. Remove from the oven and transfer to a saucepan. Bash the crab shells with sturdy kitchen implement to break them down and cover with the milk and cream. Bring this to a simmer, stirring as you go, and then turn down to the lowest setting on your stove and leave to infuse for 30 minutes.
Meanwhile, crack your eggs into a heatproof bowl. Pass the cream mix through a fine sieve over the eggs and whisk vigorously to combine. Season with salt and a good few turns of pepper and pass it through again.
To make the filling, mix the crab meat and herbs along with some skinned and deseeded diced tomato. Season with salt and pepper, and add lime zest and juice until you have a fresh and zingy mix.
Take four ovenproof ramekins with a diameter of approximately 10cm. Using a round cutter that just fits inside the dish cut out the rounds of bread, and then butter one side. Add a little of the crab mix to bottom of the ramekin and place a round of bread on top, then repeat this with more crab and bread. Add the remaining crab mix on top of the second round of bread and then cut the remaining round of bread so you have 12 half moon shapes. Overlap three across the top of each ramekin and then pour over the custard mix, dividing it between each one and going as close to the top as you can.
Retain any custard leftover – place on an ovenproof tray, cover loosely with cling film and refrigerate overnight. The following day, 30 minutes before you would like to serve the puddings, preheat an oven to 180°C fan assisted. Remove the puddings and top up with the remaining custard as some will have soaked in. Place them on the middle shelf of the oven and cook for 12 minutes. The puddings will have puffed up slightly by the time the cooking is complete. Remove from the oven and let them rest for a minute. Serve hot with a nice glass of something cold.