Makeover Apple Streusel Coffee Cake

SO I made this for people at work, and was asked to share the recipe.

Coolest part, it's lower calorie than normal coffee cakes, and still delicious enough that my boss went back for 3rds (maybe forths?)


* 1/3 cup butter, softened
* 2/3 cup sugar
* 2 eggs
* 1 teaspoon vanilla
* 2 cups all-purpose flour (or oat flour for gluten free)
* 1 teaspoon baking soda
* 1 cup greek plain yogurt
* (1/2 t xantham gum if gluten free)

TOPPING:
* 1/3 cup chopped oats (or walnuts)
* 1/3 cup packed brown sugar
* 1 teaspoon ground cinnamon
* 2 medium tart apples, peeled and thinly sliced

If I were to make it again I might add more cinnamon and a little bit of salt, but people seemed to like it the way it was :)