1.Cut along both sides of spatchcocks’ backbones; discard backbones. Cut in half between breasts. Rinse spatchcock halves under cold water; pat dry.
2.Cut leek in half crossways; chop white bottom half finely, reserve. Using kitchen string, tie green top half of leek, bay leaves, thyme, rosemary and parsley stalks into a bundle.
3.Heat half the butter in large saucepan; cook spatchcock, in batches, until browned lightly both sides. Cook reserved chopped leek, garlic, onion and bacon in same pan, stirring, about 10 minutes or until onion softens. Add flour; cook, stirring, 2 minutes. Gradually add wine and stock; bring to a boil, stirring constantly until mixture boils and thickens. Return spatchcock to pan with herb bundle, reduce heat; simmer, covered, 30 minutes.
4.Meanwhile, boil, steam or microwave potato until tender; drain. Mash potato with warmed milk and remaining butter in large bowl until smooth. Cover to keep warm.
5.Discard herb bundle. Add peas, lettuce and mint to pan; simmer, uncovered, about 5 minutes or until peas are just tender. Divide mashed potato among serving plates; top with spatchcock mixture.
Chicken pieces, quails or pigeons can be used rather than spatchcocks, if desired. Spatchcock can be made ahead up to the end of step 3; cover, refrigerate overnight.Note