Crumb Cake

Cake:
1 3/4 cup unbleached all-purpose flour
1/2 teaspoon salt
1 1/2 teaspoons baking powder
1/4 teaspoon baking soda
1/2 cup (1 stick) unsalted butter
1 cup sugar
2 eggs
1 teaspoon pure vanilla extract
3/4 cup sour cream
Crumb Topping:
2/3 cup brown sugar
3 Tablespoons flour
1/4 teaspoon fine sea salt
1/2 teaspoon ground cinnamon
1/4 teaspoon ground cardamom
3 Tablespoons melted butter
1. Preheat oven to 325 degrees. Butter a 9 inch springform pan. In a medium sized bowl, whisk together flour, salt, baking powder, and baking soda.
2. In a large bowl, cream together butter and sugar until light and fluffy. Incorporate eggs, one at a time, until smooth. Add in vanilla and sour cream. Beat until smooth. Slowly incorporate flour mixture and mix until just incorporated.
3. In another bowl, combine the dry ingredients for the crumb topping, and add in the melted butter. Mix together with a teaspoon until blended, breaking up chunks as you stir.
4. Spread batter evenly in the springform pan. Top evenly with crumb topping.  Bake cake for 45-50 minutes or until a toothpick inserted into the center of the cake comes out clean.

Found here: http://www.zupas.com/index.php/2011/02/easy-crumb-cake/