Cut eggplant into 1/2 inch slices.
Spray with canola and lay them spray side down down in a hot nonstick skillet. Let them crisp and brown on one side. Then spray other side and flip and brown slices.
Cool and cut into small chunks.
Heat remaining oil in the same pan. When hot add kalonji, cumin, red chiles and curry leaves. Let them splutter for 30 seconds.
Add all other ingredients except eggplant. Bring sauce to a simmer and add eggplant. Cover and cook for 15-20 minutes till eggplant is fully cooked.