Some folks like their chilli sauce sweet, others prefer a fair amount of tang. When making chilli sauce specifically for kebabs, you might want to keep in mind just what is on those skewers. Chicken and pork meat will take well to a sweeter sauce, while a straight veggie kebab might do better with a hotter, zestier sauce. You can be the judge when adding to this basic chilli sauce.
Heat olive oil over a medium heat in a skillet or sauce pan.
Sauté onions until tender but not quite brown. Add the garlic and jalapeños and sauté for another 2 to 3 minutes.
Add tomatoes, brown sugar and vinegar into the pan and simmer for 15 to 20 minutes, stirring occasionally.
Turn the heat down to low and continue to cook until the sauce has thickened. This can take up to an hour or longer depending on the thickness you desire. If it gets too thick, you can add a little water or broth to thin it out.
Take sauce off the heat and allow to cool. If you like your sauce chunky, you can simply add salt and pepper. For a smoother sauce, pour the cooled sauce in a blender and purée to the desired consistency.
Pour the sauce over the kebabs and let them marinate for at least 1 hour prior to placing them on the grill. Continue to brush the sauce on the kebabs while cooking.
For a sweeter sauce add a little fruit juice or canned pineapple to the pot while cooking. For a more tangy sauce, add a tablespoon of freshly grated ginger, allspice or nutmeg.