Add the rolled oats into a medium-sized heat-proof bowl. Pour boiling water over the oats and let the oatmeal mixture sit for approximately 90 minutes or until it comes to room temperature.
1 cup old fashioned rolled oats, 1-1/2 cups boiling water
Preheat the oven to 350°F. Spray a 9x13 baking dish with baking spray, set aside.
In a medium-sized bowl whisk together flour, baking soda, baking powder, cinnamon, and salt, and then set aside.
1-1/3 cups all-purpose flour, 1 teaspoon baking soda, 1/2 teaspoon baking powder, 1 teaspoon ground cinnamon, 1 pinch of fine sea salt
In a separate large bowl add sugar, brown sugar, and butter and mix until combined with an electric hand mixer.
3/4 cup granulated sugar, 3/4 cup light brown sugar, 1/2 cup unsalted butter
Add the cooled oatmeal mixture to the flour mixture and mix until combined. Then add the eggs and vanilla and mix until combined. Then scrape down the sides of the bowl. Add the flour mixture to the butter and sugar mixture and stir until just combined.
2 large eggs, 2 teaspoons vanilla extract
Pour the cake batter into the prepared cake pan and smooth out the top. Bake the cake for about 30-40 minutes or until a toothpick inserted into the center comes out clean. When finished baking, carefully remove the cake from the oven and place it on a wire rack to cool completely.
While the cake is cooling, make the cream cheese frosting by adding the cream cheese and butter in a large bowl and, using an electric hand mixer, whip the two together until the mixture is smooth. Add in the powdered sugar a little at a time until fully combined. Add the vanilla and cinnamon and mix them in, whip for 2 minutes until the frosting is light and fluffy.
8 ounces cream cheese, 1/2 cup unsalted butter, 2 cups powdered sugar, 1 teaspoon ground cinnamon
Once the cake is cooled completely, spread the cinnamon cream cheese frosting evenly over the top of the cake and serve.