Preheat oven to 220°C.
Roughly chop pumpkin into large pieces, with skin on, but seeds removed.
Halve onions and trim off the root end of the garlic bulb, again leaving skins on. Scatter these ingredients on a baking tray, drizzle with oil and roast for about 45 minutes or until pumpkin is soft. Once roasted, set aside to cool slightly.
In a large, heavy-based saucepan, melt butter and gently warm the spice until fragrant. Scrape pumpkin and onion flesh away from the skin and add to pot. If using a variety like Kent pumpkin, some of the skin may be so soft that it can simply be added along with the flesh. Squeeze the garlic bulb so the soft, roasted cloves slide out into the pot. Add water and chilli salt and bring to a boil. Simmer for half an hour before adding coconut milk and cooking for another 5 minutes.
Meanwhile, dust shallot rings with flour. Carefully heat oil in a small saucepan and once hot – the oil is hot enough if a small cube of bread makes the oil form bubbles around it on contact. Add shallots and fry until crisp and brown. Remove and place on kitchen towel to drain excess oil, then sprinkle with salt.