Preheat oven to 350 degrees. Cook sliced squash in boiling water for 7 to 10 minutes; drain well and place in a large mixing bowl. Add condensed soup, sour cream, grated carrot, chopped onion, melted butter, and ½ of the package of cornbread stufﬁng mix. Mix gently to combine, and then transfer mixture into a lightly greased 9 x 13 x 2-inch baking dish. Top evenly with remaining ½ package of stufﬁng mix. Bake in preheated oven, uncovered, for 45 minutes.