1.Preheat oven to 180ºC/350°F.
2.Heat 1 tablespoon of the oil in a medium flameproof baking dish over high heat; cook beef, turning, until browned all over. Season.
3.Roast beef about 30 minutes for medium. Transfer beef to a plate; cool. Cover; refrigerate 3 hours or overnight.
4.Place bread on baking-paper-lined large oven tray; brush with another tablespoon of the oil. Bake about 10 minutes or until golden and crisp.
5.Meanwhile, to make tuna aïoli, blend or process aïoli, tuna, anchovies and juice until smooth. Season to taste.
6.Heat remaining oil in a small frying pan; cook garlic until lightly golden. Drain on absorbent paper.
7.Thinly slice beef; arrange on a serving platter, sprinkle with garlic, capers and parsley. Serve with tuna aïoli and crisp bread.