Preheat oven to 190 degrees C. Butter a Swiss roll tray. Line it with buttered foil or buttered baking paper.
Beat the eggs until thick and lemon coloured. Gradually add 1 cup white sugar, beating constantly. Stir in water and vanilla essence. Fold in flour, baking powder and salt. Pour batter into tin.
Bake for 15 minutes. It should be springy to the touch and beginning to shrink away from the sides of the tin.
Lay out a tea towel and sprinkle it with icing sugar. Turn the Swiss roll out on the tea towel. Take off the paper or foil. Cut away crusty edges. Roll the cake up in the tea towel and leave it to cool.
Whisk together the cream, gelatine and 1 tablespoon sugar until fulffy. Fold in strawberries. Unroll the cake. Spread with the strawberry cream and roll up again. Chill. Cover the top with more whipped cream when serving.