Prepare pie crust according to recipe; roll out dough for bottom crust, line pie pan.
Preheat oven to 425 degrees.
Pour pie filling into bottom crust.
Roll out top crust, use a butter knife (non-serrated side) to cut 1-inch strips for the lattice.
Start at the center, and lay strips out in an over-n-under basket-weave fashion--leaving about 1/4-inch between strips (so the cherries peek through); crimp edges with fork tines to seal.
Beat egg until very frothy, lightly brush over crust and strips--be SURE not to get it on the filling (it doesn't look very nice); immediately sprinkle with sugar.
Bake in 425 oven for 15 minutes, then turn down to 325 and continue baking for another 30 minutes -- crust should be golden brown.
SUGGESTIONS: Use seasonal cookie cutters to create the top crust.