Add cinnamon, cloves, cumin seeds, mustard seeds, garlic, ginger, soaked dried chillies, and malt vinegar to a mixer jar. Grind until the mixture turns into a smooth, fiery paste. Scrape down the sides if needed. The vinegar binds the spices and acts as the base of Balchão’s pickled flavour.

Warm oil in a wide non-stick pan and slide in the prawns. Sauté them just until they turn light pink; avoid cooking through completely. Remove them onto a plate. This partial cooking keeps the prawns tender later, preventing them from turning rubbery when mixed with the Balchão masala.

Using the same oil, add the chopped onions and sauté until they soften and turn translucent. Stir in the chopped tomato and a small pinch of salt. Cook until the tomato collapses and becomes pulpy. This forms the mild base that balances the heat of the spice paste.

Spoon in the ground paste and mix it thoroughly with the onion-tomato mixture. Sauté until the oil begins to separate; this step is key for bringing out the vinegar and chilli flavours fully. Once the masala thickens, add the prawns and sugar. Stir and cook for a couple of minutes on low heat.

Transfer the Balchão to a bowl. Though it tastes great right away, letting it rest for a few hours allows the prawns to absorb the pickled masala even better. Serve warm for a festive meal.