Line and grease a 23 x 30-cm/9 x 12 in Swiss roll tin. Whisk the eggs and sugar until very pale and thick enough to leave a trail when the whisk is lifted out.

Carefully fold in the flour using a metal spoon. Turn the mixture into the prepared tin, spreading it out very lightly. Bake in a hot oven for 7 - 10 minutes.

Meanwhile place a clean tea-towel on a work surface, cover with greaseproof paper and dredge with sugar. Turn the hot Swiss roll on to the paper.

Trim off the edges, spread with jam and, using the cloth and paper as a guide, quickly roll up tightly. Dredge with caster sugar and cool on a wire rack.

Draw round the base of the tin on a sheet of greaseproof paper, snip in from the corners. Place in the greased tin, overlapping corners, then grease. The paper should be 5 cm (2 in) higher than the tin.