Preheat the oven to 400 F/ 200 C/ gas mark 6. Cut the eggplant in half lengthways and place on a large baking tray open side up. Brush/drizzle with a little olive oil (2-3 tablespoons) and bake for 25 minutes. Remove from the oven, set aside for 5 minutes, then carve out the middle of each eggplant leaving about 1 cm around the edges and scoop out the pulp using a melon baller or spoon. Keep the oven on.
While the eggplants are in the oven make the sauce. In a saucepan heat up the oil, add the garlic, ginger, chili, onion, stir and cook over a medium heat for 2-3 minutes until softened.
Add the passata, chopped red pepper, cumin and coriander, salt, stir, cover and bring to the boil, then simmer for about 6-7 minutes, stirring occasionally.
Add the eggplant pulp into the sauce and puree.
Place a few tablespoons of the sauce (about a quarter of the sauce) in a large baking dish spreading evenly and place the hollow eggplant halves in a single layer on top. Season with eggplant. Combine the remaining sauce with the quinoa and stir thoroughly. Adjust seasoning as necessary.
Spoon the quinoa mixture into the eggplant halves, drizzle with some olive oil, cover with foil and bake for 1 hour. Remove from the oven, set aside for 5 minutes, then serve.
You can cook the quinoa ahead and, once completely cooled, cover and refrigerate it for up to 3 days.
The sauce (minus the eggplant) can also be cooked (though not pureed) and refrigerated overnight. So that once you've scooped out the flesh of the eggplant and added it to the sauce all you have to do is puree the mixture, add the quinoa and assemble the recipe.
Once you've added the eggplant pulp into the sauce either puree it until smooth or puree partially just to combine and break up the larger pieces.
Spices: you can use tarragon or thai basil (3 tbsp each, finely chopped), add 2 teaspoons of smoked paprika or serve this dish with cilantro.