In a medium sized bowl, whisk together the wet ingredients: greek yogurt, pumpkin, eggs, brown sugar, and vanilla extract
In a separate bowl, whisk the dry ingredients: whole wheat flour, rolled oats, pumpkin pie spice, salt, baking soda, and baking powder
Add the wet ingredients to the dry ingredients, mixing with a rubber spatula until just combined (do not over mix)
Fold in the mini chocolate chips
Line 12 muffin cups with parchment paper muffin liners (these will not stick like regular muffin liners) If you use regular muffin liners, spray them with cooking spray to avoid sticking.
Distribute filling evenly (these will be large muffins)
Sprinkle on additional mini chocolate chips over the tops
Bake the pumpkin muffins at 400 degrees for 15-17 minutes, or until a toothpick inserted comes out clean