Preheat the oven to 375°F and line or grease a 12-count muffin tin. Set aside.
In a large mixing bowl, add the flour, baking powder, baking soda, cinnamon, and nutmeg. Briefly stir together to combine the dry ingredients.
2 cups all-purpose flour, ½ teaspoon baking powder, ½ teaspoon baking soda, 1 teaspoon ground cinnamon, ¼ teaspoon ground nutmeg
In a medium mixing bowl, combine the sugar, egg, vanilla yogurt, vegetable oil, and buttermilk. Whisk until combined.
¾ cup granulated sugar, 1 large egg, ¼ cup vanilla greek yogurt, ⅓ cup vegetable oil, ½ cup buttermilk
Pour the wet ingredients into the dry ones and mix until the ingredients are just combined.
Pour the batter into the muffin tins until they are ¼ full-- this should use about half of the batter.
Divide half of the crumb layer between the wells of the muffin tin. Divide the remaining half of the batter between the muffin cups and top with the remaining crumb topping.
Bake the muffins for 18-20 minutes or until a toothpick inserted into the center comes out clean.
Allow the muffins to cool on a wire rack.