For serving:
30 g capers, washed

Method
Bring a saucepan of water to the boil, reduce to a simmer, add vinegar, then break eggs onto a plate and slide into water. Cook for 3 minutes or until white is set but yolk is still soft. Remove and drain on kitchen paper or refresh in iced water and reheat just before serving.
Heat a heavy-based pan to high and add enough olive oil to coat the base. Sear tuna 2-3 minutes each side until medium rare. Remove from pan and rest 1 minute before serving.

Champ
Boil potatoes until tender and then mash. Bring milk, cream and butter to boil then gradually stir into the potatoes until they acquire a light, smooth consistency. Fold in spring onions and capers. Season to taste with salt and pepper.

Lemon and caper sauce
Heat butter in a small saucepan until nut brown in colour. Remove and discard flesh from lemon, wash skin well and dice finely. Whisk in butter and remaining ingredients and season to taste.
Place a large spoonful of champ on each plate, rest fish on side and top with warm poached egg. Drizzle with lemon and caper sauce and garnish with extra capers if desired.
Source: Australian Seafood Users Manual