Pre-heat oven to 400 degrees and line a muffin tin with 12 baking cups.

In a large bowl, mix together oats, yogurt and milk. Set aside to soak for 10 minutes.

Meanwhile, whisk together remaining dry ingredients in a small bowl: whole wheat pastry flour through ground cloves.

In a medium bowl, whisk together mashed bananas with oil and egg. Add to the soaking oat mixture and stir to combine.

Slowly add the dry ingredients to the wet ingredients. Stir in walnuts or chocolate chips.

Using an ice cream scoop or 1/4 cup measuring cup, pour batter evenly into 12 lined muffin tins. Bake until toothpick comes out clean, about 18-20 minutes.

Let cool in pan 2 minutes before transferring to a wire rack to cool completely.