Jam Roly-Poly

1. Put a deep roasting tin onto the bottom shelf of the oven, and make sure that there’s another shelf directly above it. Pull the roasting tin out on its shelf, fill two-thirds with boiling water from the kettle, then carefully slide it back in. Heat oven to 180C/160C fan/gas 4. Tear off a large sheet of foil and greaseproof paper (about 30 x 40cm). Sit the greaseproof on top of the foil and butter it.
2. Tip butter, flour and vanilla seeds into a food processor; pulse until the butter has disappeared. Tip into a mixing bowl. Stir through the suet, pour in the milk and work together with a cutlery knife until you get a sticky dough. You may need a drop more milk, depending on your flour.
3. Tip the dough out onto a floured surface, quickly pat together to smooth, then roll out to a square roughly 25 x 25cm. Spread the jam all over, leaving a gap along one edge, then roll up from the opposite edge. Pinch the jam-free edge into the dough where it meets, and pinch the ends roughly, too. Carefully lift onto the greased paper, join-side down (you might find a flat baking sheet helpful for this), loosely bring up the paper and foil around it, then scrunch together along the edges and ends to seal. The roly-poly will puff quite a bit during cooking so don’t wrap it tightly. Lift the parcel directly onto the rack above the tin and cook for 1 hr.
   1 hour
4. Let the pudding sit for 5 mins before unwrapping, then carefully open the foil and paper, and thickly slice to serve.
   5 minutes

Cooking notes

Baked goods are unforgiving with rounding — use weights rather than volumes whenever possible, and verify pan capacity if you scale up or down significantly.

For volume-to-weight conversions of any ingredient — flour, sugar, butter, salts — use the ingredient converter. To translate the recipe's oven temperature between °C, °F and gas mark, see the temperature converter.

When you scale this recipe up or down, remember that cooking time does not scale linearly. A doubled cake takes longer, but not twice as long; a doubled soup takes roughly twice as long. The cooking-time guide gives sensible starting estimates by dish geometry.