Step 1Combine the juice and 2 tablespoons sugar, whisking until the sugar is dissolved. Taste and add additional sugar as desired; the mixture should be sweet (the sweetness will fade as the granita freezes). Pour into a shallow baking dish so the mixture comes up the sides approximately 1 inch. Freeze, checking occasionally to see when ice begins to form on the top and sides, after an hour or so, and begin scraping the ice crystals into the center of the pan with a fork. Continue to freeze, scraping occasionally, until there is no more liquid in the pan. Just before serving, fluff the crystals with a fork. Serve heaped into ice cream bowls or wine glasses.