Cook the pumpkin in a large saucepan of salted, boiling water until just tender; usually 15 minutes. Strain and allow to cool to one side.
Melt the butter in a large saucepan set over a medium heat. Sweat the onion for 5-6 minutes, stirring occasionally, until softened. Add the pumpkin to the saucepan and continue to cook, stirring occasionally, for a further 5 minutes. Remove from the heat.
Pre-heat the oven to 180°C.
Place the flour and butter for the crumble topping in a food processor and pulse until the mixture resembles breadcrumbs. Transfer to a mixing bowl and season well, then stir in the cheese.
Spoon the pumpkin mixture into heatproof serving glasses, then top with the crumble. Bake on baking sheets for 20-25 minutes until the crumble is golden-brown in colour on top.
Remove and allow to stand for 5 minutes before serving.
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