Ingredients
Crumb Topping
2 ½ cups all purpose flour
1 ½ cups light brown sugar packed
½ cup granulated sugar
2 ½ teaspoon ground cinnamon
¼ teaspoon salt
1 cup unsalted butter melted
Cake
2 ¼ cups all purpose flour
1 teaspoon baking powder
1 teaspoon baking soda
½ teaspoon salt
½ cup butter softened
1 cup granulated sugar
3 large eggs at room temperature
1 cup full-fat sour cream
1 ½ teaspoons vanilla extract
Powdered sugar for dusting
Instructions
Preheat oven to 350 degrees. Grease a 9×13 inch baking pan.
In a medium bowl using a fork stir together the flour, brown sugar, granulated sugar, ground cinnamon, and salt. Drizzle in the melted butter stirring with a fork just until combined; set aside for a few minutes.
In another medium bowl whisk together flour, baking powder, baking soda, and salt.
Using a stand mixer or a hand mixer on high speed beat the butter and granulated sugar until creamy and smooth. Reduce the speed to stir and add the eggs on at a time mixing just until combined. Add the sour cream and vanilla mixing just until incorporated. Keeping the mixer on stir add the flour mixture in three intervals mixing just until combined. Scrape down the bowl and beater as needed.
Spoon the cake batter into the prepared baking pan. Use an offset spatula to even the batter. Sprinkle the crumb topping over the cake mixture and bake for 45-50 minutes or until a toothpick inserted in the center comes out mostly clean with just a few moist crumbs.
Remove from the oven and let cool for at least 45 minutes before slicing. Dust with powdered sugar before serving.