• Preheat the oven to 350°F. Spray a 9x9-inch square cake pan or baking pan with nonstick spray and then line it with parchment paper; making sure to leave a bit of overhang so you can easily lift out the coffee cake later. 

Cinnamon Sugar

• In a small bowl, whisk together the light brown sugar, flour, and cinnamon until thoroughly combined. Set aside. 
  1/2 cup light brown sugar, 1 tablespoon all-purpose flour, 2 teaspoons ground cinnamon

Cinnamon Streusel Crumble

• In a medium mixing bowl, mix together the flour, light brown sugar, and cinnamon.
  1 cup all-purpose flour, 1/2 cup light brown sugar, 1 tablespoon ground cinnamon
• Add in the cold cubed butter and pinch/press together with your fingers, until the mixture forms pea-sized clumps. Set aside. 
  1/2 cup (1 stick) unsalted butter

Applesauce Cake

• In a small bowl, whisk together the flour, baking powder, and salt. 
  2 cups all-purpose flour, 2 teaspoons baking powder, ½ teaspoon salt
• In a large bowl, whisk together the granulated sugar, light brown sugar, applesauce, Greek yogurt (or sour cream), vegetable oil, eggs, and vanilla extract until well combined. 
  1/2 cup granulated sugar, 1/2 cup light brown sugar, 1/2 cup sweetened or unsweetened applesauce, 1/2 cup plain greek yogurt , 1/3 cup vegetable oil, 2 large eggs, 2 teaspoons pure vanilla extract
• Dump the small bowl of dry ingredients into the larger bowl of wet ingredients, and stir with a wooden spoon or spatula, just until combined and no flour streaks or pockets remain in the batter. 

Assemble & Bake The Coffee Cake

• 1- Pour half of the applesauce cake batter into the prepared pan.

  2- Sprinkle all of the cinnamon sugar mixture in an even layer over top.

  3- Spoon the remaining cake batter over top and spread it out as good as possible.

  4- Sprinkle all of the crumb topping over the top for the final layer. 
• Bake for 40-50 minutes or until a toothpick inserted into the middle of the cake comes out clean, and the top of the cake and edges are lightly golden brown.
• Remove the coffee cake from the oven and allow it cool completely, in the baking pan at room temperature for about 30 minutes, and then lift it out and cut into squares for serving. Enjoy!