Gather your mise en place; get together all of the equipment needed for the recipe and gather your ingredients.

Remove the tip and root of the onion, then cut in half. Dice very finely.

Using a rasp, or alternatively a chef’s knife, mince the garlic finely.

Measure all remaining ingredients carefully.

In a medium pot over medium heat, preheat the oil. Add in the onions and cook over medium heat, stirring occasionally, until they begin to soften, roughly 3 minutes. Add in the garlic and stir, cooking for about 30 seconds. Add the tomato puree, brown sugar, vinegar, tomato paste, salt, mustard, cloves and allspice and stir until combined. Bring to a boil, then By applying heat and evaporating the water content you are decreasing in volume and concentrating flavour.reduce the heat to low and allow to simmer until thickened, about 30 minutes.

Place the mixture into a blender and blend on high until smooth.

Pass through a fine mesh strainer. Taste and adjust seasoning with salt, pepper, vinegar or sugar.