• Preheat oven to 350 degrees.
• In a small pot over medium heat, add the butter, sugar, cocoa, and salt. While stirring, bring the mixture to a boil so that the butter is melted and the sugar has dissolved. Remove from the heat, stir in water, and set aside.
• In a stand mixer, with the whisk attachment, combine the flour and baking soda. Slowly pour the hot chocolate mixture into the dry ingredients while mixing on low. Next, add the eggs one at a time, scraping down the bowl as needed. Finally, add the sour cream and mix again until the cake batter is combined.
• Pour batter into a large greased 12" x 18" sheet cake pan (or a jelly roll pan) and bake for about 20 minutes, or until the top of the cake springs back when gently pressed.
• While the cake is baking, prepare the chocolate frosting.

Chocolate Frosting

• In a stand mixer with the whisk attachment, add the room temperature butter. Whisk until the butter is light and fluffy, or about 2 minutes.
• Add the cocoa, milk, and half of the powdered sugar. Whisk on low speed until combined. Add the remaining powdered sugar and whisk again until the frosting is light and fluffy.
• When the cake is finished baking, add dollops of chocolate frosting to the warm cake. Use an offset spatula to spread the frosting evenly as it melts.
• Allow the cake to cool completely before cutting into slices and serving. Enjoy!