Pumpkin Roulade

Rolling it in a tea towel while it's warm is the trick that actually prevents the crack, and it's worth understanding why. A sponge straight from the oven is still soft and its structure hasn't fully fixed. Roll it now, around itself, and it learns that curved shape as it cools — like setting a hem. Let it cool flat first and the egg-and-flour structure sets rigid in that flat shape; ask it to curl afterwards and it fights you, and loses by splitting. The tea towel isn't decoration — it absorbs steam so the sponge doesn't turn clammy and stick to itself while it's rolled and cooling.

On the pumpkin: any dense, low-water squash will behave the same way — butternut is the easy British supermarket substitute, and it roasts the same, cool, dry side up on a tray rather than wrapped, so steam escapes instead of collecting. If you're using tinned pumpkin purée, taste it for added sugar or spice first and adjust the caster sugar and cinnamon in the recipe, because tins vary more than people expect.

The flour and baking powder are there for structure and lift, not flavour — this is why you fold them in gently rather than beat them. Beating develops gluten, gluten means chew, and chew in a sponge is the texture you don't want; a roulade should give with no resistance, almost wobble. Folding keeps the air you whisked into the eggs intact. Plain flour plus a teaspoon of baking powder does the job cheaply; self-raising flour would work too, just drop the separate baking powder or you'll get an uneven, domed rise that cracks along the ridge when rolled.

Mascarpone and whipped cream together make a filling that's rich but still holds its shape when sliced cold — mascarpone alone can be heavy and a bit flat, cream alone won't hold structure once at room temperature. Icing sugar rather than caster dissolves instantly into the fat without any grit, which matters in a cold, unbaked filling where there's no heat to melt sugar crystals for you. If you're short on mascarpone, full-fat cream cheese whipped with a touch more double cream gets you close, though it loses a bit of mascarpone's sweetness, so taste before you add all the icing sugar.

Leave a bare border of cream at the edges before rolling — not caution for its own sake, but because the filling spreads outward slightly as you roll under its own weight, and a filled-to-the-edge roulade squeezes cream out the ends and leaves you cleaning the worktop instead of the cake looking neat.

The fridge rest — at least two hours — is doing real work, not just "chilling for tradition's sake". Cold is what sets the whipped cream and mascarpone back into a firm structure after the warmth of rolling softened it; slice too soon and the roulade collapses rather than holds its spiral. The sugar-water brush at the end keeps the surface from drying out in the fridge air and gives the hazelnuts something to stick to — a thin syrup, not a glaze, just warm water with sugar stirred through until it stops feeling gritty between your fingers. White chocolate chips and chopped hazelnuts are textural contrast more than essential flavour, so swap hazelnuts for whatever nut you have toasted in a dry pan until it smells nutty rather than raw — that smell change is the doneness cue, not a clock. This feeds six comfortably as the sweet stop after a Sunday roast, sliced thin, with tea rather than coffee — it's rich enough that nobody's asking for seconds the size of the first slice.