You sure can! For best results, don't brush the tops with the egg wash or add the pretzel salt. Just bake them as normal and allow them to cool to room temperature. Place them into the freezer on the cookie sheet for 1 hour just until frozen. Place each frozen pretzel dog in a freezer safe bag and freeze until ready to use. To prepare, brush the frozen pretzels with egg wash and sprinkle with salt. Bake at 350 degrees for about 15 minutes or until warmed through and golden brown.