Peel the squash and remove the strings and the seeds. Cut the pulp into slices no more than 1/2-inch thick and season with salt and pepper. In a 12-inch saute pan over medium-high heat, saute the squash slices in olive oil until tender and browned on both sides, about 10 minutes. Add cinnamon, garlic, parsley and sugar. Season well with salt and pepper. Add a sprinkling of oil and add the vinegar and mint leaves. Toss. Arrange the squash on a large platter.
Pour the sauce over the squash and let cool. Serve cold.