Bengali Oil Splitting: The Hallmark of a Properly Cooked Base

In Bengali cooking, the visual cue that a tomato-based sauce has reached proper doneness is 'oil splitting'—when the cooking fat separates and pools at the edges of the pan. This technique, called tel chhara or tel bhasha, indicates that tomatoes have cooked long enough for their raw acidity to mellow and their natural sugars to concentrate. The process takes 10-15 minutes of patient cooking over medium heat, stirring occasionally. Watch for the transformation: first the tomatoes break down into a wet mass, then gradually thicken as moisture evaporates, and finally the oil rises to the surface in glistening pools around the edges. Rushing this stage results in harsh, acidic sauce lacking depth. Bengali cooks also add a pinch of sugar at this point—not to sweeten, but to round out flavors and balance acidity in a technique distinct from Italian cooking. The sauce should be jhol-style (brothy), not thick like Italian ragù, allowing it to coat gnocchi or rice while remaining light enough to drink.