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Grilled flank steak with fermented green chilli sauce

Recipe for grilled flank steak with fermented green chilli sauce.

By Alice Storey
  • 20 mins preparation
  • 15 mins cooking plus fermenting
  • Serves 4 - 6
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Grilled flank steak with fermented green chilli sauce
For the sauce you need fermented vegetable liquid; we use the liquid from Peace Love sauerkraut or Life in a Jar vegetables, available at health-food shops and delicatessens. Start this recipe at least five days ahead to ferment the chilli mixture.


  • 2 tsp cumin seeds, dry-roasted
  • 1 tsp whole black peppercorns
  • 6 garlic cloves, finely chopped
  • ¼ cup (loosely packed) oregano
  • 1 tbsp dried oregano
  • 125 ml (½ cup) olive oil
  • 2 tbsp red wine vinegar
  • 1 kg flank steak, trimmed, cut into thin strips
  • 3 white onions, thickly sliced into rounds
  • 4 light-green banana chillies
Fermented green chilli sauce
  • 600 gm long green chillies, halved lengthways
  • 6 garlic cloves, coarsely chopped
  • 2 spring onions, coarsely chopped
  • 60 ml (¼ cup) fermented vegetable liquid
  • 2½ tbsp raw caster sugar
  • 2 tbsp finely grated ginger
  • 150 gm drained canned tomatillos, coarsely chopped
  • ½ cup (loosely packed) coriander, coarsely chopped
  • Juice of 1 lime or to taste
  • 2 tbsp olive oil


  • 1
    For fermented green chilli sauce, discard seeds from half the chillies, then coarsely chop. Add to food processor with garlic, spring onions, vegetable liquid, 2 tbsp caster sugar, ginger and 1 tbsp fine sea salt flakes, process until finely chopped, then transfer to a sterile 1-litre jar. Tap jar gently on the bench to remove air bubbles, cover with lid, but do not seal and set aside at room temperature to ferment (3-5 days, depending on climate). Stir with a sterile spoon every day, wiping sides of the jar with a clean paper towel. The chilli sauce will be ready when there are small bubbles in the jar and it has a slightly fermented smell. Seal lid and refrigerate for up to a month. Makes about 600ml.
  • 2
    Crush cumin seeds, peppercorns and 2 tsp salt with a mortar and pestle. Add garlic, oregano, and dried oregano, pound to a paste, then stir in 80ml olive oil and vinegar. Place flank steak in a large container or bowl, add marinade, toss to coat and refrigerate to marinate (8 hours to overnight).
  • 3
    Combine 125ml fermented green chilli sauce, tomatillos, coriander, lime juice, olive oil and remaining sugar in a bowl and season to taste.
  • 4
    Preheat a char-grill or barbecue to medium-high. Thread steak onto large skewers and set aside. Brush onions and banana chillies with remaining olive oil and grill, turning occasionally, until charred and tender (8-10 minutes).
  • 5
    Char-grill steak, turning occasionally, until charred and cooked to your liking (4-5 minutes for medium-rare). Set aside to rest (5 minutes), then serve with fermented green-chilli sauce and char-grilled onions and banana chillies.


Drink Suggestion: Juicy young cabernet franc. Drink suggestion by Max Allen