Preheat the oven to 350°F/180°C and line 2 8-inch cake pans with parchment paper rounds.

Add flour, sugar, baking powder, baking soda, and salt to the bowl of a stand mixer fitted with the paddle attachment. Mix on low, spinning about 5 times.

Add butter and beat on low for 5 minutes until the texture looks like wet sand.

Add oil, eggs, vanilla, and espresso powder. Mix on low until a batter forms. Slowly pour in the buttermilk and mix until well combined.

Evenly portion the batter between the cake pans. Bake for 25-30 minutes. The cakes are done when a toothpick inserted in the center comes out clean.

Remove the cakes from the oven and cool for 20 minutes on a wire cooling rack. Turn the pans upside down onto the rack to release them. Let cool completely before frosting.

Add softened butter to the bowl of a stand mixer fitted with the paddle attachment. Beat for 5 minutes on medium high speed until creamy.

Add half of the powdered sugar and mix on low for 2 minutes. Beat in the second half on medium speed until smooth. Mix in vanilla, spices, and salt.

Pour in the milk 1 teaspoon at a time until the desired consistency is reached.

Add a tablespoon of buttercream to the middle of a cake board or stand. Fan it out with an offset spatula.

Place one cake layer on the board and spread an even layer of frosting over it. Place the second cake layer on top with the flat side up.

Spread a thin layer of frosting (crumb coat) all over the cake. Chill in the freezer for 20 minutes or until the frosting is solid.

Apply a final layer of frosting. Pipe a boarder and add cinnamon sticks and star anise as decoration if desired. Slice and enjoy!