1Preheat oven to 425F degrees. Line muffin tin with baking cups or spray with nonstick spray. Set aside.
2Make the streusel first by combining all ingredients in a small bowl. Set aside.
3n a medium bowl, gently toss together the flour, cinnamon, baking soda, baking powder, and salt. Set aside. Using an electric stand or hand mixer, beat the sugar, butter, and egg in a large bowl until fluffy, scraping down the sides as needed. On low speed, beat in the mashed bananas and yogurt. By hand, stir in the dry ingredients mixing until everything is just combined. Do not overmix.
4Layer one spoonful of batter into the muffin cup. Sprinkle with streusel. Layer another spoonful on top and layer with more streusel. Continue to layer batter and streusel into each muffin tin.
5Bake muffins for 5 minutes at 425F degrees. Lower temperature dial down to 350F degrees and continue to bake for about 14 more minutes until the muffins are set and lightly browned. Allow to cool for 5 minutes in the tins and transfer to wire rack to cool completely.