To make the spice mix, combine together ground cumin, ground fennel, ground coriander, red chili powder and ground fenugreek. Set aside.

Preheat oven to 200 C or 400 F. Line a large baking tray with baking paper. 

Spread tomatoes, onions, garlic, ginger and green chilies in one layer onto the prepared tray.

Sprinkle with spice mix.

Drizzle with olive oil. Toss. Season with salt and pepper.

Roast for about 30-40 minutes or until the vegetables are tender.

Remove from oven. Cool completely.

Once cooled, place tomatoes in a blender, and process to a smooth puree. Add a little broth (stock) if needed.

Meanwhile, bring broth (stock) and oregano to a boil in a large saucepan. Season with salt and pepper.

Reduce heat and simmer for about 5 minutes.

Add pureed tomato mixture. Simmer for 2 minutes. Strain if you want a very smooth texture.

Top with yogurt and coriander (cilantro) or mint leaves. Serve with croutons.