Make Ahead - Bake cornbread recipe. Allow to sit in pan on counter overnight to dry out. OR make cornbread and allow to cool. Cut into cubes, place in single layer on baking sheet in 250°F oven for 30 minutes to dry out. Use immediately.
Preheat oven to 350°F. Lightly grease 9 x 13 baking dish.
Place raisins in a small bowl and add vegetable stock to cover, about 1 cup. Set raisins aside to soften.
Heat butter in medium size skillet until melted. Add onions and celery and saute over medium-high heat until translucent about 3 minutes. Remove from heat.
Cut cornbread into cubes in baking pan. Transfer to a large mixing bowl.
Add the sage, thyme, salt, pepper and sauteed vegetables to the cornbread. Toss to combine. Add the egg and raisins with liquid to the cornbread mixture. Stir with wooden spoon to combine. Mixture will be wet and crumbly. If too dry - add more vegetable broth 1/4 cup at a time until mixture is wet, but still hold together.
Transfer to prepared baking dish and bake uncovered for 40 -45 minutes until cornbread is dry and golden on top.