01 -
Heat the vegetable oil in a medium saucepan over medium heat. Add the finely chopped onion and sauté for 5 to 7 minutes, stirring occasionally, until the onion is soft and golden brown.
02 -
Stir in the all-purpose flour, mixing thoroughly to create a roux. Cook for 1 to 2 minutes to eliminate the raw flour taste. Add the mild curry powder, ground turmeric, ground ginger, and minced garlic. Stir well and cook for an additional minute until the spices are aromatic.
03 -
Gradually pour in the water or vegetable broth, whisking constantly to achieve a smooth consistency without lumps. Continue whisking until the mixture begins to thicken.
04 -
Reduce the heat to low and allow the sauce to simmer gently for 10 to 15 minutes, stirring occasionally. Adjust the texture as needed by adding a small amount of water or broth if the sauce becomes too thick.
05 -
Incorporate the granulated sugar, salt, and black pepper. For a sharp finish, stir in the distilled vinegar, if desired. Taste and adjust seasoning as necessary.
06 -
Once the sauce is smooth and flavors are balanced, remove from heat and serve immediately over freshly cooked fries or with battered fish as a classic accompaniment.