1. Prepare Deep-Dish Pizza Dough and let it rise.
2. While dough rises, prepare filling. In a medium frying pan heat tomato oil over moderate heat; add onion and cook, stirring often, until soft but not browned. Mix in garlic, then remove from heat.
3. In a medium bowl mix ricotta cheese with dried tomatoes and parsley; stir in cooked onion mixture.
4. Divide dough into two equal portions. Roll each half out on a floured suface to a 12-inch circle. Spread half of the ricotta filling over half of each circle of dough, leaving about a 1/2-inch margin.
5. Sprinkle half of each circle with half of the prosciutto strips and 1 cup of the mozarella cheese. Fold circles in halves over filling, moistening and pinching edges together (or pressing with tines of a fork) to seal.
6. Preheat oven to 450~ F. Sprinkle a large, greased baking sheet lightly with cornmeal. Place calzone well apart on prepared baking sheet. Let rise until puffy (12 to 15 minutes). Brush tops lightly with olive oil, then serve hot.