Preheat the oven to 400°F. Grease a 9x9 inch pan very well with butter.
Add the sweet potatoes to a large pot of water and boil until soft enough to stick a fork through, about 15 minutes. Remove from the pot and drain. Mash in a bowl until very well mashed. Set aside to cool off. It can be warm, just not hot, or you risk scrambling the eggs.
Meanwhile, while the sweet potatoes cool, mix up the dry ingredients. In a mixing bowl, combine 1 and ¼ cups of flour, 1 cup of cornmeal, ½ cup of brown sugar, 1 tablespoon of baking powder, 1 teaspoon of baking soda, 1 teaspoon of kosher salt, 2 teaspoons of ground cinnamon, ¼ teaspoon of nutmeg, and ¼ teaspoon of cloves. Whisk to incorporate the ingredients well. Set aside.
In a separate large bowl, once the sweet potatoes have cooled, combine the sweet potato mash with 1 and ¾ cups of milk, 3 tablespoons of vinegar, 6 tablespoons of melted butter, and 2 eggs. Whisk until well combined. The mixture will be a little lumpy, but that's okay, it will all come together in the end.
Add in the dry ingredients about ⅓ at a time, mixing to incorporate before adding more dry ingredients. Switch to a rubber spatula to continue folding in the rest of the ingredients really gently, being sure to scrape the sides and the bottom of the bowl. Once everything is incorporated, stop mixing!
Transfer to the greased baking dish, and use a rubber spatula to spread the batter in an even layer. Bake for 35-40 minutes, until the top is golden brown and a toothpick comes out clean with a few crumbs.
Immediately add some pats of butter over top to let it melt into the hot cornbread. Cut into squares, and serve with more butter, flaky salt, and honey if desired. Enjoy!
Store leftovers in an airtight container at room temperature for up to 4 days. It can then be transferred to the fridge for an additional 3 days.