Mix together the flour, suet and salt. Gradually add enough of the water
to make a light dough. Roll out the dough on a lightly floured surface to
a rectangle about 1 cm/0.5 in thick and sprinkle with the onions, bacon
and sage. Roll up like a Swiss (jelly) roll and curl into a greased
pudding basin. Cover the basin and place in a large saucepan. Add boiling
water to the saucepan to come half-way up the sides of the basin, cover
and steam for 2.5 hours, topping up with boiling water as necessary, until
the pastry (paste) is cooked through.