Heat the oven to 375°F (190°C). Grease a 9-inch square baking dish with butter or nonstick spray.
Whisk the eggs, whole milk, sour cream, cooled melted butter, and honey in a large bowl until the eggs are fully blended.
Add both boxes of corn muffin mix. Fold gently with a spatula just until no dry pockets remain. Do not beat the batter smooth; a few small lumps are fine.
Spread the batter evenly in the prepared dish. Bake for 23 to 28 minutes, until the top is golden, the center springs back lightly, and a toothpick shows a few moist crumbs.
Brush the hot cornbread with 1 tablespoon melted butter. Rest for 10 minutes before cutting into 16 squares and serving warm.