For the pasta, place the flour and 3 of the eggs into a food processor and pulse until it forms small crumbs. Remove the mixture from the food processor and pull together to form a dough.
Knead the dough lightly for 2-3 minutes until it is smooth and elastic then wrap in cling film and place in the fridge for 20 minutes.
Flour a pasta machine and turn it to the lowest (thickest) setting. Feed the dough through the machine, turning the handle with one hand and holding the dough as it comes through the machine with the other.
Change the setting on the pasta machine to the next-thickest setting, flour it again and feed the pasta sheet through the machine again, as before. Repeat this process 3-4 more times, flouring the machine and changing the setting down each time - it helps to cut the pasta into smaller pieces as you work to prevent it drying out. Cover any pasta you are not working on with cling film. Set the pasta aside. Any extra dough can be frozen for use on another occasion.
Cut the lobster in half lengthways and remove all the meat – taking care to keep the claw meat intact. Cut the lobster meat into 1cm/½in thick slices.
To make the tortellini, use a circular cutter to make 9cm/4in circles of pasta. Place a piece of tail meat on each circle and top with a basil leaf. Brush a little water on the edge of the pasta and fold over the top to make a semi-circle. Press down lightly to seal. Wrap the corners of the semi-circle around your index finger and join together to make a tortellini shape. You need 6 tortellini per person.
For the sauce, heat a frying pan until hot and add the butter and lobster shell and fry for 5-6 minutes. Add the chopped shallot, garlic, celery, carrot and thyme and cook gently for 3-4 minutes. Add the brandy, let it flambé then cook for a couple of minutes and add the stock. Bring to a boil and cook gently for a further 8-10 minutes. Finish with the cream and cook for a further 1-2 minutes.
Ladle the sauce in batches into a food processor and blend to a fine purée.
To cook the ravioli, bring a large pan of salted water to the boil and gently lower the ravioli into the pan. Cook for 1-2 minutes until they float to the top of the water then remove with a slotted spoon and drain on kitchen paper. Toss in the sauce.
To serve, heat a large saucepan of boiling water and blanch the samphire for 1-2 minutes. Drain well. Heat a frying pan and add the butter. Once melted, add the samphire and toss in the butter until hot. Place the samphire in the bottom of each serving bowl and top with 6 tortellini, then spoon over the sauce and garnish with tomato and chives.