For the cake:

1. Preheat the oven to 350°F.
2. Mix the wet ingredients: In a large mixing bowl, beat together the sugar, vegetable oil, eggs, and vanilla extract until well incorporated. Scrape down the bowl as needed. Next mix in the sour cream and beat until well combined.
3. Combine the dry ingredients: In a separate bowl combine the remaining dry ingredients and sift together. Add half the dry ingredients, and half the coffee, and beat on low speed just until the flour starts to incorporate. Repeat until all ingredients are added and combined. Use a spatula to scrape down the sides of the bowl and stir the batter from the bottom to the top to ensure it’s well mixed.
4. Pour the batter into a 9-inch by 13-inch pan and bake at 350°F for 28-32 minutes, keeping a careful eye on the baking during the last few minutes. Remove from the oven and allow to cool completely. 

For the frosting:

1. Cut the butter into pieces. Using the paddle attachment, whip the butter for 5-7 minutes, scraping down the bowl occasionally, and beating until the butter is whipped and fluffy.
2. Add 2 cups of powdered sugar and espresso powder and mix on low speed until incorporated into butter. Next, add the Kahlua and vanilla extract and beat until well combined.
3. Finally, add the last two cups of powdered sugar and the heavy cream. Beat on low speed until the sugar is incorporated then increase speed to medium-high and beat for 3 minutes to whip the frosting. Spread over cooled cake. Top with sprinkles.