Prepare the cornbread following the recipe instructions. Allow the bread to cool completely (preferably overnight) before using it to make the stuffing.
Preheat the oven to 425F.
Slice the cooled and semi-dried out cornbread into small 1" cubes. Add them to a bowl and set aside.
Heat the oil in a large skillet over medium heat. Add the celery, shallots, and garlic and saute until the garlic is fragrant. Add the mushrooms, herbs and season with salt and pepper. Continue to cook until the mushrooms are completely soft, about 6 - 7 minutes.
Add the vegetables to the bowl with the cornbread, along with the milk and broth. Stir to combine. Transfer the contents of the bowl to a 9x13 baking dish. Spread the stuffing evenly out in the dish then pop in the oven and cook for about 15 - 20 minutes until the top is golden brown.
Reheat as needed and enjoy!
Notes
Store in an airtight container in the fridge for up to 4 days, or in the freezer for up to 2 months. Reheat in the oven or microwave.