In a large bowl, whip heavy cream until stiff peaks are just about to form. Beat in vanilla and sugar until soft peaks form and then set in the refrigerator until ready to serve.
In a large mixing bowl, whisk together the flour and the eggs. Gradually add in the milk and water, stirring to combine. Add the salt and butter; beat until smooth. Heat a lightly oiled griddle or frying pan over medium high heat. Pour or scoop the batter onto the griddle, using approximately ¼ cup for each crepe. Tilt the pan with a circular motion so that the batter coats the surface evenly. Cook the crepe for about 2 minutes, until the bottom is light brown. Loosen with a spatula, turn and cook the other side. Serve hot with whipped cream and jam.