To make lemon parsley seasoning, melt the butter in a large frying pan; cook celery, stirring, until softened. Add onion and garlic, cook, stirring, until fragrant. Combine onion mixture in a large bowl with remaining ingredients.

Preheat oven to moderate, 180°C (160°C fan- forced).

Discard neck from turkey. Rinse turkey under cold water; pat dry inside and out with absorbent paper. Fill neck cavity loosely with lemon parsley seasoning; secure skin over opening with toothpicks. Fill large cavity loosely with lemon parsley seasoning; reserve remaining seasoning. Tie legs together with kitchen string; tuck wings under.

Place turkey on oiled wire rack in a large flameproof baking dish. Brush turkey all over with half the butter. Rub a little salt into skin. Pour the water into the dish. Cover dish tightly with greased foil; roast in moderate oven for 2 hours. Uncover turkey; brush with remaining butter. Roast, uncovered, in a moderate oven for a further 1 hour or until browned all over and cooked through, brushing with pan juices every 20 minutes. (To test if turkey is cooked, insert a skewer into the thigh; if juices are clear, it is ready.) Remove turkey from dish, cover turkey; stand for 20 minutes.

Increase oven temperature to very hot, 240°C (220°C fan-forced).

Lightly oil 12 mini-muffin pans. Place 1 tablespoon of reserved lemon parsley seasoning in each pan. Bake in very hot oven for 10 minutes or until they are browned and crisp.

To make gravy, pour turkey pan juices from dish into a medium jug; reserve 2 tablespoons of fat from the top; discard remaining fat on surface of juices. Heat the fat in same baking dish, add flour; cook, stirring, until mixture is well browned. Gradually stir in reserved pan juices and stock; bring to the boil. Simmer, stirring, until gravy thickens slightly. Stir in jelly and mint. Season to taste with salt and pepper. Strain gravy into a jug.

Serve turkey with seasoning muffins and gravy.