• Preheat the oven to 350°F/175°C and line a 9×9 inch square pan with parchment paper. Gently grease the other sides that aren't covered with parchment paper with oil and set aside. Combine brown sugar and cinnamon in a small bowl and set aside. This will be used later.
  1/4 cup dark brown sugar, 1/2 tsp cinnamon

For the streusel

• In a medium sized bowl, add flour, brown sugar, white sugar, cinnamon, and melted butter (make sure the butter is not hot). Using a fork, mix this until combined. Then add 1 tbsp of extra flour on top and using your hands, crumble the streusel into smaller and larger pieces. You may need 1 more tbsp of flour if the butter hasn't been completely absorbed. Set aside in the fridge when done.
  1/4 cup white sugar, 1/4 cup brown sugar, 3/4 cups all-purpose flour + 1-2 tbsp on the side, 6 tbsp butter, 1/2 tsp cinnamon

For the coffee cake

• Into a bowl, add in flour, baking soda, cornstarch, baking powder, and salt. Mix together and set aside.
  2 cups all-purpose flour, 1 teaspoon baking soda, 1 teaspoon baking powder, 1/2 tsp salt, 1 tbsp cornstarch
• In a large bowl (Big enough for all the ingredients), add white sugar and oil and whisk together. Then add in eggs, applesauce, sour cream, and vanilla. Whisk together until well combined.
  1/2 cup oil, 3/4 cups white sugar, 1/2 cup sour cream, 1 cup unsweetened applesauce, 2 large eggs, 1 tsp vanilla
• Add the dry ingredients into the wet and using a spatula, gently fold to create a soft cake batter. Do not over-mix the batter. Once no dry streaks show, stop mixing.
• Time to layer the coffee cake! Add half of the batter into your prepared pan and spread evenly. Then sprinkle all of the cinnamon sugar topping and about 5-6 tbsps of the streusel. Add the remaining half of your batter on top and spread as evenly as you can, and then the rest of your streusel on top.
• Bake the cake for 35-50 minutes, or until a toothpick inserted comes out dry. Mine took 50 minutes. If it is wet, then the cake hasn’t fully baked yet so continue to bake at 5 minute intervals. Allow it to cool completely.
• Once cooled, slice and enjoy! This applesauce coffee cake is best served fresh or next day. My favourite way to eat it is warm. You can store it on your coutner for 3 days and in the refrigerator for up to a week.