Preheat your oven to 350°F (175°C) and grease a 9 x 13 inch baking pan.

In a medium bowl, whisk together quick cooking oatmeal, all-purpose flour, baking powder, and salt until combined.

In a large bowl, beat room-temperature butter and packed brown sugar until light and fluffy. Add eggs and vanilla and blend until smooth.

Gently stir the dry ingredient mixture into the creamy butter mixture until just combined.

In a saucepan over low heat, melt chocolate chips, sweetened condensed milk, and additional butter until smooth. Stir in optional nuts if desired.

Press half of the oat mixture into the greased pan, pour the fudge layer on top, and crumble remaining oat mixture over fudge.

Bake for about 25 minutes or until edges are golden brown and a toothpick comes out clean.

Allow bars to cool completely in the pan on a wire rack before cutting into squares.