Comme un coq en pâte

Literally: Like a rooster in pastry

Example: “Chez sa grand-mère, le petit vit comme un coq en pâte.” — At his grandmother's, the little boy lives in clover.

English equivalent: To be in clover

Origin: Older French said coq de panier (basket rooster) or coq de bagage (baggage rooster), for the bird carried to market with great care so it would fetch the best price — that care is where the comfort in the phrase comes from. The pâte (pastry) joins it in the 17th century, and the joke turns grim if you follow it through: a bird bound for a pâté en croûte (pâté baked inside a pastry crust) really is indulged and fattened first, then laid on soft pastry and wrapped in a gentle warmth whose purpose it has no idea of. Rooster pâté was never actually common, so what seems to have happened is a crossing of the older expression with en pâte read simply as somewhere soft.