1. Preheat your oven to 350°F (175°C) and grease two 9-inch round cake pans. Line the bottoms with parchment paper.
2. In a large mixing bowl, combine the flour, sugar, cocoa powder, baking powder, baking soda, and salt.
3. In another bowl, whisk together the eggs, buttermilk, vegetable oil, and vanilla extract until well combined.
4. Gradually add the wet ingredients to the dry ingredients and mix until smooth.
5. Stir in the hot brewed coffee and Kahlua until the batter is well combined and smooth.
6. Divide the batter evenly between the prepared cake pans.
7. Bake in the preheated oven for 30-35 minutes or until a toothpick inserted into the center comes out clean.
8. Allow the cakes to cool in the pans for 10 minutes, then remove them from the pans and transfer them to a wire rack to cool completely.

For Strawberry Buttercream:

1. In a mixing bowl, beat the softened butter until creamy and fluffy.
2. Gradually add the powdered sugar and beat until well combined.
3. Add the strawberry puree and vanilla extract, and continue to beat until the frosting is smooth and creamy.
4. Once the cakes are completely cooled, spread a layer of strawberry buttercream on top of one cake layer.
5. Place the second cake layer on top and frost the entire cake with the remaining strawberry buttercream.
6. Decorate with fresh strawberries if desired.