Wrap 1 potato in a paper towel and microwave on high for 2 minutes. Turn and repeat. Do this until the potato is slightly soft to the touch. Repeat with the other potatoes. Set aside and allow the potatoes to cool. When they are cool, cut into wedges.

Preheat your outdoor grill or indoor grill pan.

Brush the wedges with olive oil and sprinkle with salt, pepper and fresh rosemary. Grill on each side for 3-4 minutes until you get nice grill marks. To a large saucepan over medium heat add olive oil. Add the chopped onion and sauté for about 5 minutes until softened. Add the grated ginger and garlic, stir and cook for 1 minute. Add the curry, garam masala, ground coriander, smoked paprika, salt and pepper. Stir until mixed with the onions for about 1 minute until fragrant. Add the tomato paste and stir into the onion and spices. Add the white wine vinegar (stand back and do not breathe in the fumes) and stir to mix.

Add the tomato puree/passata and mix well. Simmer for 15 minutes until it is thick and the constancy of ketchup. If it gets too thick, add water, 1 tablespoon at a time. Blend in the blender or use an immersion blender to make smooth. Transfer to a sealed container.