For the Cake:
1 1/2 cups all-purpose flour
1 1/2 cups cake flour
1 tablespoon baking powder
1/2 teaspoon salt
1 tablespoon ground cinnamon
2 sticks butter, softened to room temperature
1 3/4 cups fine or superfine sugar
4 large eggs, room temperature
1 tablespoon vanilla extract
1 1/4 cups whole milk, warmed to room temperature
For the Buttercream:
4 1/2 sticks butter, softened to room temperature
1 cup light brown sugar, packed
2 teaspoons ground cinnamon
8-9 cups confectioner’s (powdered) sugar
1 teaspoon vanilla extract
1/2 cup of half and half, plus more if needed
Optional: Whole cinnamon sticks for garnish
To Bake the Cake:
-Preheat oven to 325°F.
-Butter and flour two 8- or 9-inch round cake pans.
-In a mixing bowl, whisk together the flours, baking powder, salt and cinnamon. Set aside.
-Cream together the butter and sugar until fluffy and pale in colour.
-Beat the eggs in one at a time, fully incorporating each egg and scraping down the bowl between each addition.
-Add about 1/3 of the milk, beat to incorporate, then 1/3 of the flour, again beating to incorporate.
-Repeat this process, scraping down the bowl as necessary, until all of the milk and flour are added and mixed in evenly.
-Divide the batter evenly between the two pans and bake, rotating midway through, for about 35 minutes or until the cake tests done.
-Let the cakes cool in the pan on a rack for 5 minutes before turning out onto the racks to finish cooling.
To Make the Buttercream:
-Beat together the butter, brown sugar and cinnamon until fluffy and pale in colour.
-Add 6 cups of the confectioner’s sugar and the vanilla extract and beat, starting on low and moving up -to high, until it is fully incorporated.
-Scrape down the bowl and add the half and half. Beat to incorporate again.
-Add another 2 cups of the confectioner’s sugar and beat, starting on low and moving up to high, until fully incorporated. Check the consistency of the buttercream. If it needs to be thicker, add the remaining confectioner’s sugar. If it is too thick, add more half and half a teaspoon at a time, beating after each addition, until it reaches the consistency you like.
To Assemble and Frost the Cake:
-Level out your cooled cakes and cut each into two even layers.
-Place one layer on a cake plate then add a layer of buttercream, spreading to the edges and evening out as you go. Repeat with the remaining layers.
-Frost the top and sides of the cake with the remaining buttercream.
-If desired, garnish the top of the cake with whole cinnamon sticks.
Cover and refrigerate for at least an hour before slicing.
-Store leftovers tightly covered in the refrigerator.