Salt the eggplant and stand for 20 minutes, rinse then pat dry.
Heat the oil in a wok or saucepan to 180C and fry the eggplant slices and brussels sprouts in batches until golden brown. Drain well.
The brussels sprouts will spit when you add them to the oil, so cover the wok with a wire mesh for the first minute of cooking until the spitting stops.
Heat a wok or medium saucepan over medium heat and add about 2 tsp of oil.
Add the fennel, cumin, cassia, cardamom and red chillies and fry for a minute until fragrant.
Add the onion and the ginger and garlic paste and fry for 4 minutes until starting to brown.
Add the kadai masala ingredients and stir to combine.
Add the tomatoes, tomato sauce and about 1½ cups of water and bring to a simmer.
Simmer for 10 minutes, then stir through the eggplant and brussels sprouts.
Taste and adjust seasoning.
Stir through the fenugreek leaves and stand for 10 minutes before serving.
Garnish with sliced ginger and green chillies.