Ingredients:
- all-purpose flour
- granulated sugar
- baking powder
- salt
- unsalted butter, softened and cubed
- buttermilk, room temperature
- large eggs
- vanilla bean paste
- unsalted butter, very soft (for swirl)
- light brown sugar, packed (for swirl)
- all-purpose flour (for swirl)
- ground Saigon cinnamon (for swirl)
- full-fat cream cheese, slightly chilled (for frosting)
- unsalted butter, room temperature (for frosting)
- powdered sugar (for frosting)
- heavy cream (for frosting)
- sea salt (for frosting)
Instructions:
- Preheat oven to 350°F (175°C) and grease two 8-inch round cake pans with parchment paper. In a stand mixer, combine 375g flour, 300g granulated sugar, baking powder, and salt. Mix on low speed.
- Add 225g cubed butter to the dry ingredients one piece at a time on low speed until the texture resembles coarse sand. In a separate bowl, whisk buttermilk, eggs, and vanilla. Slowly pour into the flour mixture and beat for 90 seconds to develop structure.
- In a small bowl, mash the swirl ingredients (115g soft butter, brown sugar, 2 tbsp flour, and cinnamon) with a fork until a thick, uniform paste forms.
- Divide half the cake batter between the pans. Drop dollops of the cinnamon paste over the batter and swirl with a knife. Top with remaining batter and more cinnamon paste, swirling again. Bake for 35 minutes or until a skewer comes out clean.
- Prepare the frosting by beating 450g cream cheese and 115g butter until smooth. Gradually add powdered sugar, heavy cream, and sea salt. Beat until fluffy. Frost the cooled cake layers generously.