For the spring pea soup, heat the butter and oil in a large saucepan, when hot fry the onions until soft. Add the peas and cook for a further 3-4 minutes.
Bring the stock to the boil then pour it over the peas and onions. Return to the boil and cook for a further 3-4 minutes, or until the peas are tender.
Drain the peas, reserving a little of the cooking stock. Blend the peas and cooked onions in a food processor with a little of the cooking stock.
Pass through a sieve and set aside to cool in a bowl set over ice to retain the green colour.
For the garnish, mix the olives, Little Gem lettuce, basil, chives, lemon zest, lime juice and zest with the crab meat, then season with salt and pepper. Add a little olive oil, to taste. Set aside.
To serve, place the dressed crab in rings in the centre of shallow bowls. Pour the pea soup around and add a quenelle of double cream on top. Drizzle over a little extra olive oil and season the cream with a little black pepper.