For the cornbread: Preheat the oven to 350 degrees F. Butter an 8-inch cast-iron skillet or an 8-inch square baking pan.
Combine the cornmeal, flour, sugar, baking powder and salt in a large mixing bowl.
Combine the milk, honey, vanilla, eggs and butter in another mixing bowl and whisk to thoroughly combine. Make a well in the dry ingredients and pour the wet ingredients into the well. Mix gently to combine. When the mixture has just come together, transfer it to the prepared skillet or baking pan. Bake until golden around the edges and a tester inserted in the center comes out clean, 25 to 30 minutes. Let cool before cutting or wrapping in plastic wrap. Allow to sit, wrapped at room temperature, 1 to 2 days.
For the cornbread stuffing: Preheat the oven to 350 degrees F.
Cut the cornbread into 1-inch cubes and place in a large bowl. Set aside.
Coat a large saute pan over medium heat with olive oil, then add the onions and celery. Sprinkle with salt and cook the vegetables until they start to become soft and are very aromatic, 5 to 7 minutes. Add the garlic and cook for 1 to 2 minutes. Stir in the chorizo and cook until it browns, about 7 minutes. Sprinkle in the sage and rosemary and remove from the heat.
Toss the chorizo mixture in the bowl with the cornbread cubes. Add the chicken stock and knead with your hands until the cornbread is very moist and wet. Taste to check for seasoning and season with salt, if needed (it does). Transfer to a 9-by-13-inch ovenproof serving dish.
Roast until the stuffing is hot all the way through and crusty on top, about 30 minutes. Serve.