Slice eggplant into 2 cm round pieces then salt well on both sides and let sit for 15 minutes.
Preheat oven to 190c and roast portobello mushrooms seasoned with olive oil, salt, pepper, and dried thyme for 20 minutes.
Caramelize red onions in a pan with olive oil and balsamic reduction for around 25 minutes.
Create wet mix with plain flour, corn flour, water, and salt. Prepare dry mix with breadcrumbs, panko, paprika, salt, parsley, and oregano.
Dry eggplant slices, bread them in wet mix and then into dry mix, coat well.
Shallow fry breaded eggplant slices in olive oil for 2-3 minutes each side until brown.
Toast bun and spread Heinz [Seriously] Good Vegan Smokey Mayo, layer mushrooms, caramelized onions, fried eggplant, and capsicum on the bun.
Top with the other half of the bun and enjoy!