Preheat oven to 350 degrees F and grease a 9x13 nonstick brownie pan. (I lined my pan with parchment paper to make it easier to lift the bars out and cut).
In a mixing bowl, combine butter and brown sugar until creamed. Mix in eggs and vanilla.
Add in flour, baking soda and salt and mix until combined.
Stir in oats.
Spread 2/3 of cookie mixture into the pan.
In a medium saucepan over medium heat, combine fudge ingredients until melted.
Spread fudge over cookie mixture in the pan.
Drop the remaining cookie mixture by spoonfuls on top of the fudge layer.
Bake for 25-30 minutes or until top is brown.
Cool completely before cutting.