Beat the egg white in a bowl and add castor sugar. Add corn flour and vinegar to it and mix well. Fill the mixture in a piping bag. On a tray, spread butter sheets. Squeeze the egg white mixture in the piping bag on to these sheets in different patterns as a base for Strawberry Pavlova. To make it dry, bake the Pavlova base in a pre heated oven under a temperature of 100 to 120'C. Keep the Pavlova base on a slate, smear whipped cream on it and place the strawberries over it. Make different layers with the Pavlova base and cream. Place strawberry marshmallows on a new layer, and continue making layers on top. Put some cut strawberries on the top layer. Garnish it with castor sugar and chocolate hearts.