Preheat oven to 425 degrees F. Line 2 muffin cavities with about 18 paper liners; set aside. Meanwhile, in a large bowl, combine the flour, baking powder, salt, cinnamon and nutmeg. Gently stir in the wet ingredients until batter just about comes together - batter will remain lumpy, and don't overmix! Overmixing leads to tough muffins. Set batter aside.

In a medium bowl, combine the crumble ingredients. Stir until thick, coarse crumbs form. Set aside.

Fill muffin cups about 2/3 full with the muffin batter. Top with a heaping Tablespoon or two of the crumble mixture. Bake for approx. 5 minutes, then reduce the temperature to 375 degrees F and continue to bake for approx. 15-20 minutes or until the tops are golden brown and a toothpick inserted near the center comes out clean or with moist crumbs. Cool for about 10 minutes before serving.