Preheat the oven to 350°F. Spray a half-sheet pan (18x13 inches) with non-stick cooking spray.

In a large bowl, whisk together flour, granulated sugar, brown sugar, cocoa powder, baking powder, baking soda, and salt.

In a separate bowl, mix sour cream, vegetable oil, eggs, buttermilk, apple cider vinegar, and vanilla extract until smooth.

Add the wet ingredients to the dry ingredients and mix for about a minute.

Slowly stir in hot coffee until fully combined. The batter will be thin—this is normal.

Pour the batter into the greased half-sheet pan and bake for 20-25 minutes, or until a toothpick inserted in the center comes out clean.

Tip: The batter may rise close to the edge, so place a baking sheet underneath to catch any potential spills.

In a small saucepan, melt butter over medium heat.

Stir in sugar and sour cream, mixing constantly. Bring to a low boil and let simmer for 30 seconds.

Remove from heat and whisk in cocoa powder, salt, and dark chocolate chips until smooth.

If the frosting thickens while waiting for the cake to cool, return it to low heat and stir in 1-2 tablespoons of milk until it reaches a spreadable consistency.

Let the cake cool for 10 minutes, then pour the warm frosting over the top and spread evenly.

For a decorative touch, sprinkle the edges with your favorite sprinkles—because what's a cake without sprinkles?