I took this recipe from Britt who is the kind of cook who thinks everyone knows this stuff already:

Pre-heat the oven to 220 degrees Celsius. Cut your aubergine in half. Make criss-cross incisions in each half. Pour lots of oil, getting it into the cuts. Add your spices (paprika, chilli, cumin, tumeric etc) and rub. Roast it, face down, for around 15-20 minutes.

During this time, make a paste — I chop and mix red onion, garlic, grated Parmigiano-Reggiano, and tomato paste with some more spices and some salt and pepper. When the aubergine is mushy, flip the sides over carefully, cover the tops with paste, and put it back in the oven for around 30 minutes at 180 degrees Celsius.

I usually serve with rice made with onions, garlic, and tomatoes.