To roast the carrots: peel and chop carrots in 1 inch segments. Preheat oven to 400 degrees. Line baking sheet with foil. Drizzle carrots with a small amount of oil. Pull the foil up around the carrots and completely enclose them. Bake for 40-50 minutes.
Preheat oven to 350 degrees. Grease a 9 inch cake pan.
In a medium bowl, combine flour, baking powder & soda, cinnamon, nutmeg and salt. Combine.
In a blender or food processor, combine carrots, milk, brown sugar, oil, yogurt, eggs, and vanilla. Blend until smooth.
Add carrot mixture to flour bowl. Stir until combined.
Pour into prepared cake pan.
In a small bowl, combine topping ingredients. Sprinkle evenly over the batter in the cake pan.
Bake for 30 minutes or until firm in the center or toothpick comes out clean.