Mix together the flour, bicarbonate of
soda, spices and salt. Beat the egg until thick and pale, then beat in
the sugar until the mixture is pale and creamy. Stir in the pumpkin
and lemon juice. Fold in the flour mixture. In a clean bowl, beat the
egg whites until stiff. Fold into the cake mix and spread in a greased
and lined 30 x 12 cm/12 x 8 in Swiss roll tin (jelly roll pan) and
sprinkle the walnuts over the top. Bake in a preheated oven at
190°C/375°F/gas mark 5 for 10 minutes until springy to the touch. Sift
the icing sugar over a clean tea towel (dish cloth) and turn the cake
out on to the towel. Remove the lining paper and roll up the cake and
towel, then leave to cool.
To make the filling, gradually beat the sugar into the cream cheese
and vanilla essence until you have a spreadable mixture. Unroll the
cake and spread the filling over the top. Roll up the cake again and
chill before serving sprinkled with a little more icing sugar.