Place the blood f="http://www.foodterms.com/encyclopedia/orange/index.html" class="crosslink" debug="16 28">orange juice, sugar and pepper in a bowl and whisk to incorporate. Pour the blood orange mixture into a large baking dish and place in the freezer. Scrape and crush the lumps with a fork every half an hour until the granita freezes, approximately 1 1/2 hours. Scrape with a fork to lighten the texture before serving. Spoon into glasses and serve.