Preheat oven to 400°F (200°C) and line a baking sheet with parchment paper.
Wash the pumpkin, cut it in half and scrape out the seeds. Brush the pumpkin with olive oil, sprinkle with salt and place it cut side down on the baking sheet.
Roast one half for about 25 minutes, remove from the oven and cut it into 1-inch chunks. Set aside.
Continue roasting the other half for 45 minutes. Once very soft, remove from the oven, let cool a few minutes and discard the skin. Place the pumpkin flesh in a blender with the coconut milk, non-dairy yogurt, water, spices, maple syrup, and salt. Blend on high speed until very smooth.
Heat the oil in a large skillet over medium heat. Once hot, add garlic and ginger and cook until garlic is soft, about 3 minutes. Add pumpkin chunks, jackfruit and cook for another 5 minutes, stirring regularly to make sure it doesn't stick to the bottom.
Pour in the pumpkin sauce and stir to coat. Let simmer for 5-7 minutes, adding more water if needed until it reaches a thick, yet creamy consistency. Tastes and adjust seasonings if needed.
Serve warm on a bed of rice, or as is. This curry will keep for up to 3 days in the refrigerator.