Combine the flour, salt and sugar in the bowl of a food processor and pulse. Add the cold butter and pulse until the butter is the size of peas. Slowly add the ice water, 1 tablespoon at a time, pulsing, just until the dough starts to come together.
Gather the dough together and flatten onto a piece of plastic wrap. Wrap the dough and chill in the refrigerator for 2 hours.
When you are ready to use the dough, roll dough into one large circle. Place the rolled tart dough onto a parchment-lined baking sheet.
Preheat oven to 425 degrees. Combine the sliced peach, plums, and raspberries in a bowl. Add the sugar and 1 tablespoon of flour. Mix gently and spoon the fruit mixture into the center of the tart dough leaving approximately a 3-inch border. Bring the dough up over the fruit and pleat the dough (see photo above). Brush the pleated edge with heavy cream and sprinkle with raw sugar. Scatter small pieces of butter over the fruit.
Bake crostata in the center of the oven for approximately 30 minutes, or until crust begins to turn a golden brown.
Remove from oven. Cool for at least 15 minutes to make sure the fruit sets and serve with fresh whipped cream.