Melt the 1/4 cup of butter in a skillet over low heat. Add the pecans and toss to coat. Toast, stirring often, for 5 minutes or until fragrant and toasted.
Add the cake mix to the bowl of your mixer. Add the eggs. Add in milk in place of the water called for on the box. Add the butter or oil as called for on the box of mix. Add in 1 teaspoon of vanilla.
Beat together as directed on the box. During the last 30 seconds of mixing, add the pecans to the batter.
Pour batter into two greased 9 inch cake pan and bake as directed on the box.
Allow cakes to cool completely before frosting.
To make the frosting:
In a medium sauce pan, melt together the butter, cream, and brown sugar. Bring to a boil and boil for one minute.
Remove from the heat and add to the bowl of a stand mixer. Allow to cool for 15 minutes.
Add the vanilla and powdered sugar to the bowl and beat together until well combined.
Add milk or cream to get the correct consistency, as needed.