In a medium nonreactive saucepan, combine the diced tomatoes, onion, mango, raisins, tamarind concentrate, brown sugar, vinegar, molasses, garlic, ginger, scotch bonnet pepper, salt, and water. Stir well.

Tie the cloves, allspice berries, peppercorns, cinnamon stick, and bay leaf into a cheesecloth sachet and add it to the pot. Bring to a simmer over medium heat, then reduce to low and simmer, stirring occasionally, for 30–35 minutes, until the fruit has fully broken down and the mixture has reduced by about a third.

Remove and discard the spice sachet. Remove the scotch bonnet pepper now for a milder sauce, or leave it in a few minutes longer for more heat.

Puree the mixture with an immersion blender (or transfer to a countertop blender) until completely smooth, about 1–2 minutes.

Strain the sauce through a fine mesh strainer into a clean bowl, pressing with a spatula to extract as much liquid as possible. Discard the leftover pulp.

Taste the sauce and adjust as needed — more brown sugar if too sharp, more vinegar if too sweet, a pinch of cayenne if you want more heat.

Pour the warm sauce into sterilized glass bottles or jars. Let cool uncapped on the counter for 20 minutes, then seal and refrigerate.