Steamed Butternut-Squash Sponge with Brown Sugar and Nutmeg

Peel and cube the butternut squash into 2cm pieces. Place in a steamer basket over simmering water and steam for 12-15 minutes until completely tender when pierced with a knife.

Transfer the steamed squash to a bowl and mash thoroughly with a fork until smooth. Allow to cool to room temperature — this puree should be lump-free before folding into the batter.

In a large bowl, cream the softened butter and brown sugar together with a wooden spoon or electric mixer for 3-4 minutes until pale, light, and noticeably increased in volume.

Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next. The mixture may look slightly curdled — this is perfectly normal and will come together once the flour is added.

Sift the all-purpose flour, baking powder, and nutmeg together over the egg mixture. Fold gently with a spatula until just combined — do not overwork or the sponge will be tough.

Fold in the cooled butternut-squash puree until evenly distributed throughout the batter. The mixture should be thick and smooth.

Generously butter a 1-litre pudding basin or heatproof bowl. Pour the sponge batter in and tap gently on the counter to release any air pockets. Cover tightly with a double layer of pleated baking parchment or a pudding cloth secured with string.

Place in a large pot with enough water to reach halfway up the sides of the basin. Bring to a vigorous boil, then reduce to a steady simmer. Steam for 25-30 minutes — do not lift the lid during cooking.

Carefully remove the basin from the pot using oven gloves. Pierce the centre of the sponge with a skewer; it should come out clean when fully cooked. If not, return to the steamer for a further 5 minutes and test again.

Allow the sponge to rest in the basin for 5 minutes only — just long enough to firm up slightly. Run a knife around the edge, place a warm serving plate over the top, and invert in one confident motion.

Serve immediately while the sponge is still warm and fragrant, with proper vanilla custard poured over, if you like. A dusting of extra brown sugar is a lovely finishing touch.