Heat oven to 375 degrees.
Lightly oil a large baking sheet. In large skillet, heat oil over medium heat; add onion and sauté 5 minutes.
Stir in oregano, then mixed vegetables, and salt and pepper to taste. Cook, stirring occasionally, until vegetables have thawed – about 10 minutes. Stir in 1/2 cup cheese and the pecans.
Remove dough from package and spread to about a 14 1/2 inch square. Divide dough into 4 equal squares. Transfer 1 square to baking sheet and top with a heaping cupful of vegetable-pecan mixture. Fold over one corner of dough to meet opposite corner; pinch and roll edges together to enclose filling, creating a triangle turnover shape.
Lightly brush top with water, sprinkle with a teaspoon of remaining Parmesan and some black pepper. Make two small slashes in top. Set aside on baking sheet and repeat to make 3 more calzones.
Bake calzones 15 – 20 minutes or until well browned. Cool slightly before serving.
Nutrition information per serving (using 1/4 tsp salt and pepper): calories: 459; protein: 16g; carbohydrate: 55g; saturated fat: 4g; monounsaturated fat: 11g; polyunsaturated fat: 5g; cholesterol: 10 mg; fiber: 8g; sodium: 638 mg.