Preheat oven to 350°F. In a stand mixer, blend together the butter, yogurt and eggs until pale and creamy. Add in cake mix, pumpkin purée, and spices until smooth.
Grease a 4-tin mini loaf pan. Spoon 1/4 of the dough into each tin, about halfway full. Mix together the cinnamon and sugar in a small bowl. Sprinkle each tin with 1 tablespoon of the cinnamon sugar mixture until the dough is covered.
Bake on 350°F for 28-30 minutes until loaves are doubled in size and a toothpick comes clean. Let cool for 5 minutes, then serve. Enjoy!