Melt vegan butter in a saucepan over medium heat. Stir in mango nectar, habanero sauce, brown sugar, vinegar, and salt. Simmer for about 10 minutes until the sauce is glossy, then let it cool.

In a large mixing bowl, whisk together the flour, cornstarch, baking powder, paprika, onion powder, garlic powder, ground coriander, and salt until well mixed.

Pour a portion of the dry ingredients into a bowl and gradually combine it with lemon sparkling water, mixing until you achieve a thin batter consistency.

Clean the oyster mushrooms and dip each one into the wet batter, ensuring they are fully coated, then roll them in the remaining dry batter for a crispy finish.

Heat your cooking oil to 350°F (175°C) in a deep frying pan. Carefully fry the coated mushrooms in batches for about 3-6 minutes, or until they are golden brown and crispy.

Once fried, immediately toss the hot mushrooms in the cooled mango habanero sauce to coat them thoroughly. Serve right away for the best texture and flavor.