Heat a large nonstick pan over medium-high heat. When hot, add the oil along with the ginger, garlic, and jalapeño. Cook until fragrant, about 1 minute. Add the garam masala, nigella, coriander, cumin, cardamom, cloves, and cinnamon. Cook, stirring constantly until fragrant, about 1 minute more. Add the mango, vinegar, sweetener, Dijon, and glucomann. Bring to a boil and then reduce the heat to a simmer and cook until thickened, about 10 minutes. Whisk in butter until smooth then transfer to a bowl and set aside.