Preheat oven to 350°
Spray a loaf pan with cooking spray
Measure flour and level with a knife
Mix dry ingredients in a medium bowl
Put sugar and butter in a large bowl and beat until well blended
Add eggs one at a time and beat well
Add in the pumpkin puree, yogurt and vanilla and beat until blended
Add dry ingredients to wet ingredients, in three parts, until just blended
Stir in chocolate chips or other add-ins if you are using
Pour batter into prepared pan
Bake at 350° for 45 minutes or until a toothpick comes out clean
Cool for 10 minutes in the pan, then slide bread out and place on a baking rack until cool