Jam Roly-Poly with Custard

Ingredients

• 300g plain flour
• 120ml cold milk
• 25g caster sugar
• 50g unsalted butter, softened
• 100g vegetarian suet
• 1 tsp baking powder
• 200g strawberry jam
• 4 egg yolks
• 1 tbsp cornflour, dissolved
• 600ml whole milk
• 60g caster sugar
• 1 vanilla pod, seeds scraped (optional)

Method

1. Heat the oven to 200°C fan / 220°C / gas 7. In a large bowl, rub the suet into the flour with the baking powder, caster sugar and a good pinch of salt until it looks like fine breadcrumbs — about 2 minutes of light fingertip work. The salt is small but non-negotiable; without it the sponge tastes flat against the jam.
2. Pour in the cold milk and stir with a round-bladed knife to bring it together into a soft, slightly sticky dough — stop the moment it comes together, overworking turns suet pastry tough. Tip onto a lightly floured board and roll into a rectangle roughly 30 x 25cm and about 1cm thick.
3. Smear the softened butter across the dough, then spoon over a scant 200g of jam, spreading it almost to the edges but leaving a 2cm border so it doesn't escape in the oven. Roll up tightly from the long edge into a snug log and pinch the seam shut, tucking the ends under.
4. Wrap the roll loosely in baking parchment, then in foil, leaving a good two fingers of slack for it to puff — wrap it tight and the sponge has nowhere to go. Bake for 35–40 minutes until risen and golden and the centre springs back when pressed; pull the foil off for the final 5 minutes to glaze the crust.
5. While it bakes, warm the milk with the split vanilla pod and seeds in a heavy pan until steaming and just shy of a simmer — you want wisps of steam, not bubbles. Whisk the yolks with the caster sugar, a tiny pinch of salt and the dissolved cornflour for a minute until paler and thicker; the salt sharpens the vanilla and stops the custard tasting one-note sweet.
6. Pour a ladle of hot milk into the yolks, whisking constantly to temper them — straight in and you'll have sweet scrambled egg. Tip the lot back into the pan and cook over a low heat, stirring with a wooden spoon in slow figure-of-eights, for 4–6 minutes until the custard coats the back of the spoon and runs thickly when you draw a finger through it. Don't let it boil. Taste it — adjust for salt and sugar now, while you can still stir it in.
7. Rest the roly-poly for 5 minutes, then slice thickly with a serrated knife — you want fat pinwheels of golden sponge with molten jam spiralling through. Plate the slices in warm bowls, drown them in hot vanilla custard, spoon over the warmed extra jam, and finish with a light dusting of icing sugar at the table.