Pulse flour, three eggs, and olive oil in a food processor until crumbs form.
Knead dough on a floured surface for 3 minutes until smooth then chill for 20 minutes.
Feed dough through a pasta machine starting at the thickest setting.
Roll the pasta thinner by decreasing machine settings while flouring between passes.
Repeat until desired thickness is reached and cover unused pasta with cling film.
Combine crab meats, lemon juice, paprika, and parsley in a bowl and season.
Stamp 6cm discs from the pasta and place crab filling on each.
Brush edges with egg wash, fold into crescents, and twist edges to seal.
Blanch parsley in boiling water for 30 seconds then refresh in ice water and chop.
Sauté onion in butter then add peas and stock and bring to a boil.
Blend the mixture with blanched parsley, strain into a pan, and simmer.
Boil carrots for one minute and leeks for two minutes then drain and oil.
Cook tortellini in boiling salted water for 2 minutes until they float.
Serve tortellini in the broth topped with vegetables and chervil sprigs.