How to Make It
In a medium saucepan, heat the oil over medium high heat until hot. Sauté the onion and garlic in the oil with 1/2 teaspoon salt and 1/4 teaspoon pepper until golden, about 6 minutes. Stir in the mustard, coriander, bay and chile and cook until fragrant and mustard seeds begin to pop and crackle, about 3 minutes more.
Stir in the mango, vinegar, and sugar and bring to a boil. Boil the chutney until thickened, 10 to 12 minutes. Let cool to room temperature, season with salt and serve.