method
1. Preheat the oven to 400°F (200°C).
2. Hollow out each loaf with a sharp knife to leave a thick shell. Place on a baking tray.
3. Peel and chop the onion. Wipe and thickly slice the mushrooms. Melt the butter in a saucepan, add the onion and fry till transparent. Add the mushrooms and fry for 2 minutes. Stir in the flour and cook for 1 minute. Gradually add the mushroom soup and bring to the boil, stirring constantly. Simmer for 2 minutes, then remove from the heat and allow to cool slightly.
4. Beat the egg yolks and cream into the mushroom sauce. Drain and flake the tuna and add to the sauce with the lemon juice. Season to taste.
5. Divide the hot tuna stuffing between the loaves and sprinkle with the paprika. Bake in the centre of the oven for about 25 minutes till bubbling and golden.
6. Arrange the loaves on a warmed serving dish and garnish each with a slice of lemon. Serve immediately.
