Place 1/2 cup butter in a 13" x 9" pan; heat in oven at 425° for 4 minutes.
Combine cornmeal and next 5 ingredients; whisk in 3 eggs and buttermilk.
Pour hot butter into batter, stirring until blended. Pour batter into pan.
Bake, uncovered, at 425° for 30 minutes or until golden brown. Cool. Crumble cornbread into a large bowl; stir in breadcrumbs, and set aside.
Melt remaining 1/2 cup butter in a skillet over medium heat; add onion and celery, and sauté until tender. Stir in sage; sauté 1 minute. Stir vegetables, remaining 4 eggs, chicken broth, and pepper into cornbread mixture. Fill a lightly greased 9" x 5" loafpan with 8 cups unbaked cornbread dressing. (Prepare Cornbread Dressing Croquettes with remaining dressing.) Press into pan firmly; invert dressing loaf onto a baking sheet, and remove pan.
Bake at 375° for 1 1/2 hours (or until internal temperature reaches 160°). Cool overnight. Slice into 1/2" slices. Place on lightly greased baking sheet. Bake at 425° for 30 minutes. Cool completely on baking sheet. Top toasted cornbread slices with turkey and cranberry sauce and your favorite sandwich fixin's.