Best Selling Crumb Cake

Just found this recipe in family circle magazine and can't wait to try it. Looked here on recipezaar and could not find one like it.

• Ready In: 1 hr
• Serves: 25

Ingredients

• Cake

• 1 (18 1/4ounce) box  yellow cake mix
• 1 1⁄4 cups sour cream
• 1⁄3 cup  vegetable oil
• 3  eggs
• 1  teaspoon ground cinnamon
• 1⁄2 teaspoon ground nutmeg

• Crumb Topping

• 3 3⁄4 cups all-purpose flour
• 3⁄4 cup  packed light brown sugar
• 2  teaspoons cinnamon
• 1⁄2 teaspoon nutmeg
• 1 1⁄2 cups unsalted butter, melted

• Sour Cream Glaze

• 10  tablespoons confectioners' sugar
• 2  tablespoons sour cream

Directions

1. Heat oven to 350. Grease a 15x10x1-inch baking pan. Lightly dust pan with flour; shake out any excess flour.
2. Cake: Combine cake mix, sour cream, oil, eggs, cinnamon and nutmeg in large bowl. Beat according to package directions. Pour batter into prepared pan.
3. Bake at 350 for 20 minutes or until toothpick inserted in center comes out clean.
4. Topping: Blend flour, brown sugar, cinnamon, nutmeg and melted butter in medium bowl until mixture is evenly moistened and clumps together.
5. Remove cake from oven. Sprinkle with crumbs (this will be a thick layer). Return to oven; bake 15 minutes or until crumbs are slightly set. Remove pan to wire rack and let cool completly.
6. Glaze: Whisk 8 tablespoons of the confectioner's sugar with the sour cream in a bowl. Dust top of cake evenly with remaining 2 tablespoons confectioners sugar. Drizzle with glaze. Store cake, tightly covered at room temperature for up to 3 days.