1½ tbspextra-virgin olive oil4aged sirloin steaks on the bone (about 300gm each)500 gmBrussels sprouts, halved (smaller heads left whole)1small onion, finely diced1garlic clove, shaved on a mandolin1 cup(loosely packed) flat-leaf parsleyJuiceof ½ lemon, or to taste4eggsTo serve:Dijon mustard
Heat 2 tsp oil in a large frying pan over high heat, add steaks, season to taste and cook, turning once, until cooked to your liking (8-9 minutes for medium-rare). Transfer to a warm plate, cover with foil, set aside to rest and wipe out pan.
Meanwhile, cook Brussels sprouts in a saucepan of boiling salted water until just tender (2-4 minutes), then drain well.
Add remaining oil to frying pan, add onion and garlic and stir until just tender (3-4 minutes), then add Brussels sprouts and stir until browned and just tender (4-6 minutes). Stir in parsley and lemon juice and keep warm.
Poach eggs in a saucepan of simmering water until cooked to your liking (3 minutes for soft-poached).
Place steaks on plates, top with Brussels sprouts, then egg, season to taste and serve hot with Dijon mustard.