Skin the tomatoes by blanching in boiling water then cooling in ice water.
Sieve the seeds to collect juice and tear the tomato flesh.
Char the onion and unpeeled garlic in a hot pan, then peel and chop finely.
Dry fry the chillies for 5 minutes until they lighten in colour.
Soak the chillies in cola and a splash of water for 15 minutes.
Sauté the onion with oregano, coriander, and pepper until soft.
Add garlic, tomatoes, juice, cloves, and cumin then simmer for 10 minutes.
Mix in orange juice, vinegar, and chillies then blend until smooth.
Sieve the mixture, boil, and simmer for 30 minutes before adding cocoa powder.
Cook for 15 minutes until it reaches a pouring consistency.
Adjust flavors to taste and pour into sterilised bottles.