Preheat the oven to 350°F (175°C) and grease a 13-inch by 9-inch baking pan.

In a medium bowl, whisk together the all-purpose flour, baking soda, and salt. Set aside.

Using a hand mixer or stand mixer, cream together the unsalted butter and light brown sugar until smooth. Add the eggs and vanilla extract, and mix until combined.

Gradually add the dry ingredients to the wet mixture and mix until just combined.

Fold in the quick oats using a spatula.

Spread two-thirds of the dough into the prepared pan, pressing it down to form an even layer. Set aside the remaining dough for topping.

In a heavy-bottom saucepan, combine the semi-sweet chocolate chips, sweetened condensed milk, unsalted butter, and vanilla extract.

Heat over medium heat, stirring constantly until the chocolate is melted and the mixture is smooth.

Stir in the chopped pecans, then remove from heat.

Pour the chocolate pecan fudge layer over the oatmeal cookie base and spread evenly.

Take small clumps of the reserved oatmeal cookie dough and scatter them over the fudge layer.

Bake at 350°F (175°C) for 25-30 minutes, or until the top is golden brown and the fudge is shiny.

Allow the bars to cool for at least 15 minutes before cutting into squares.