Step 1

Preheat the oven to 375 degrees Fahrenheit.

Step 2

Spray a jelly roll pan (15x10inches) with nonstick spray.

Step 3

In a large bowl combine the flour, sugar, baking soda and salt. Whisk together.

Step 4

Add your butter and water to a sauce pan and bring to a boil over medium high heat.

Step 5

Remove from heat and pour into the flour mixture. Stir until combined.

Step 6

Add in the eggs, sour cream, and vanilla extract and stir it all together.

Step 7

Pour cake batter into the prepared pan.

Step 8

Bake the cake for 18-23 minutes, or until a toothpick inserted in the center comes out clean (a few crumbs are okay).

Step 9

Cool the pan for 20 minutes.

Step 10

Add your butter and milk to a medium sauce pan and cook over low heat until the butter melts.

Step 11

Raise temperature to a medium heat and bring to a boil.

Step 12

Add the powdered sugar and vanilla extract to a bowl.

Step 13

Pour the melted butter mixture over the powdered sugar, and whisk together till nice and smooth.

Step 14

Pour frosting over the warm cake.

Step 15

Allow to cool completely before slicing and serving.