1. Place all ingredients in a large bowl and press firmly with a pestle or spoon until ingredients are well mixed. Transfer into a jar and press down to ensure liquid covers the ingredients. Put a weight or lid on top (or tuck in with extra bay leaves) to ensure ingredients stay submerged. Loosely seal jar.
2. Leave in a warm place for a few days until the tomatoes start fermenting – you’ll see bubbles forming and the tomatoes will taste sour. Loosen the lid daily to ‘burp’ the jar. Place in fridge when tomatoes have attained a sourness that pleases you.
3. Relish will keep for four weeks in the fridge; the flavour will continue to develop.