Preheat oven to 375°F. Line a muffin tin with 12 muffin liners and spray with oil.
Mix flour and baking soda with a whisk in a medium bowl.
In a large bowl with a hand mixer, mix and cream the butter and sugar on medium setting for about 2 minutes.
In a small bowl, beat the egg whites and vanilla with a whisk, add to bowl with butter/sugar mixture.
Mix in the yogurt, then flour mixture and mix on low speed until combined, 1 minute.
With a spatula, fold in the chocolate chips and spoon to lined muffin tins about ¾ filled (I used an ice cream scoop).
Bake at 375° or until a toothpick inserted in the center comes out clean, about 16 to 18 minutes. Let cool before eating.
