In a large bowl, whisk together both flours, baking powder, baking soda, cinnamon, nutmeg, and salt until evenly combined

In another bowl, mix eggs, yogurt, mashed banana, brown sugar, oil, and vanilla until smooth and creamy

Gradually fold the dry ingredients into the wet mixture until just combined, keeping the batter slightly thick

Gently stir in grated carrots, raisins, and chopped walnuts until evenly distributed

Spoon the batter into the muffin cups, filling each about three-quarters full

Bake until the tops are golden and a toothpick inserted comes out with a few moist crumbs

Let the muffins cool briefly in the tray, then transfer to a rack to cool completely

Beat cream cheese and yogurt together until smooth and fluffy

Add honey and vanilla, mixing until creamy and lightly sweet

Spread the frosting over cooled muffins and finish with a light sprinkle of cinnamon