1. In a bowl, mix chicken with Swiss cheese, pimientos, onion, and pepper.
2. In a 1 1/2- to 2-quart pan, mix broth with cornstarch. Add cream cheese. Whisk over high heat until mixture is boiling (it will be very thick), 2 to 3 minutes. Scrape over chicken mixture and combine well, adding salt to taste.
3. On a lightly floured board, unroll pizza crust dough. Cut each rectangle crosswise into thirds, for six empanadas, or quarters, for eight pastries. On one end of each piece of dough, mound about 5 tablespoons chicken mixture if making six pastries, about 3 tablespoons for eight. Fold other end of dough over filling to form a rectangle, then fold edges together and pinch to seal.
4. Gently place empanadas, slightly apart, on an oiled 12- by 15-inch baking sheet (you'll need two for eight pastries). In a small bowl, beat egg to blend. Brush generously over each pastry.
5. Bake in a 375° regular or convection oven until empanadas are very richly browned, 22 to 25 minutes (10 to 12 in convection oven). Transfer to a rack and let cool at least 10 minutes. Serve hot or warm.
Nutritional analysis per empanada.