Melt 2 tablespoons butter in a large skillet over medium-low heat. Add onion, garlic, carrots, and fennel; cook until vegetables are tender, about 10 minutes. Remove from heat.
In a large bowl, combine cornbread and sourdough. Add vegetables, herbs, prunes, and pears; season with salt and pepper.
Melt remaining 4 tablespoons of butter. Add melted butter and turkey stock to stuffing mixture. Toss to combine; let cool.