Divide the dough into four equal pieces. Roll or stretch the dough into a 6 to 8 inch oval. Brush the surface of the dough with the Dijon mustard, leaving a 1 inch border around the edges.
Layer two slices of cheese, two slices of ham and ½ cup shredded chicken on the dough leaving a 1 inch border around the edges.
Fold the dough over the chicken and press the edges together to seal. Pinch tightly to avoid the cheese leaking out during baking.
Repeat with the remaining dough and other ingredients.
Place the calzones on a baking sheet dusted with cornmeal.
Brush the surface of the calzones with the egg.
Bake for 12 to 15 minutes or until puffed and golden brown. Serve immediately
Notes
To freeze: Assemble the calzones as instructed (up to step 5) and place on a clean baking sheet. Freeze for 4 hours and then wrap individually in plastic wrap. Wrap again in foil and store in the freezer for up to 2 months.