Peel the eggplant and cut into cubes. Sprinkle with salt and let sit for 20-30 minutes. Rinse and pat dry.
Heat olive oil in a large pan over medium heat. Add mustard seeds and let them pop.
Add onion, garlic, and ginger. Sauté until soft and fragrant.
Stir in turmeric, cumin, coriander, and chili flakes. Add eggplant and stir to coat.
Cover and cook on medium-low heat for 10-12 minutes, stirring occasionally. If dry, add water.
Increase heat to medium. Add mushrooms and cook for 2 minutes. Add shrimp, sprinkle with salt, and cook until pink.
Lower heat to low. Stir in coconut milk, stirring constantly. Simmer gently for 2 minutes.
Turn off heat. Stir in black vinegar. Garnish with parsley or fennel fronds.