1.Preheat oven to 200°C (180°C fan-forced).
2.Using a mortar and pestle, grind the seeds together until coarsely crushed. Add salt, mixed spice and pepper, mix well. Remove a third of the spice mixture and reserve. Brush beef with oil, rub remaining spice mixture all over beef.
3.Roast beef, uncovered, about 1 1/2 hours for rare, or until cooked as desired. Cover, stand, 15 minutes, before carving. Meanwhile, toast remaining spice mixture in a dry pan until fragrant, allow to cool.
4.For garlic mayonnaise, combine all ingredients in a small bowl. Serve beef with garlic mayonnaise and toasted spice mixture.
Ask the butcher to tie beef with string between ribs to retain a neat shape while cooking.Note