At least a day before serving, prepare cornbread: Heat oven to 450 degrees F.
Mix cornmeal, salt and baking soda in large mixing bowl. Add buttermilk and eggs; whisk until well blended. Put butter into 10-inch cast iron skillet or 9-inch square baking pan and heat in oven until melted and bubbling.
Remove from oven, swirl butter to coat skillet or pan, then pour butter into cornbread batter, mixing well. Spread batter in skillet or pan and bake 25 – 30 minutes or until cornbread is golden brown and crusty. Cool ten minutes; remove from skillet or pan and cool completely. Tear cornbread into large bite-size pieces and set aside, uncovered, overnight to dry out.
To make Dressing: Heat oven to 325 degrees F.
Heat 4 tablespoons butter and the bacon fat in large skillet over medium heat. Add onions, celery, and shallots and cook 5 minutes. Add thyme and sage; cook, stirring often, until vegetables are tender but not browned – about 15 minutes.
In a large bowl, toss together the pecans, cornbread pieces, and vegetable mixture until well combined. Melt the remaining 4 tablespoons butter; mix with chicken broth and eggs. Pour over dressing ingredients and mix well. Transfer to buttered 13″ x 9″ casserole and cover with foil. Bake 30 minutes. Remove foil and bake 15 – 20 minutes longer or until golden.
Nutrition information per serving: calories: 454; protein: 10g ; carbs: 26g ; saturated fat: 11g ; monounsaturated fat: 17g ; polyunsaturated fat: 6g ; cholesterol: 159mg ; fiber: 5g ; sodium: 669mg.