Add chickpea water, mustard, and Vinegar in a food processor.
¼ Cup chickpea water, 2 tsp mustard powder, 1 tablespoon vinegar
Start processing till you get a smooth texture (5 minutes)
Slowly add oil and keep on processing it.
1-¼ cup oil
When it is almost thick, add salt, sweetener, and any flavorings if you are adding.
¼ teaspoon salt, 1 tablespoon sweetener
Taste and adjust as required.