Marrow bone with chimichurri and caramelised onion

1.Place marrow bones cut-side up in a single layer in an oven tray, scatter salt over, cover and refrigerate for 20 hours.

2.Meanwhile, for caramelised onion, heat a large frying pan over medium-high heat. Add oil then onion, stir occasionally until onion starts to become translucent (4-5 minutes), reduce heat to low-medium, stir occasionally until deeply caramelised (25-30 minutes), season to taste and keep warm.

3.Meanwhile, for chimichurri, pound garlic and jalapeño in a mortar and pestle to a smooth paste, transfer to a bowl, combine with remaining ingredients, season to taste with sea salt and set aside.

4.Preheat oven to 220C. Rinse marrow bones under cold running water, pat dry with absorbent paper, place cut-side up on an oven tray and roast until cooked through (4-6 minutes). Butter both sides of bread slices. Heat a large frying pan over medium heat, add bread and cook, turning once, until toasted (1-2 minutes each side), then halve diagonally and keep warm. Transfer to plates with marrow bones, top with chimichurri and caramelised onion and serve hot.