Preheat oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan.
In a large bowl, combine cake mix, pudding mix, eggs, oil, and water. Beat with an electric mixer until well combined.
Pour batter into prepared pan and bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean.
While the cake is baking, prepare the icing. In a saucepan, melt butter. Add sugar and milk, and bring to a boil. Boil for 1 minute, stirring constantly.
Remove from heat and stir in vanilla extract and pecans.
As soon as the cake comes out of the oven, pour the icing evenly over the top. Let cool completely before serving.
Notes
Enjoy with a scoop of vanilla ice cream for an extra special treat!