Preheat your oven to 350°F and line an 8×8-inch pan with parchment paper and nonstick spray.
Mix together the ingredients for the base and topping. Once you’ve added the cold butter, use your hands to combine everything thoroughly.
Split the mixture into 3/4 and press the majority into the base of the prepared pan.
In a saucepan over low heat, combine the ingredients for the fudge center, stirring constantly until smooth. Pour this mixture evenly over the base.
Crumble the remaining oat mixture on top.
Bake for 30 minutes or until the topping is golden brown.
Let the bars cool for 30 minutes, then refrigerate for at least 2 hours before cutting into squares.