Generously spray a 13-inch x 9-inch baking pan with non-stick cooking spray and set it aside.

In a medium bowl, whisk together 1 ½ cups all-purpose flour, ½ teaspoon baking soda, and ½ teaspoon salt. Set aside.

Using an electric mixer, beat together ½ cup of softened unsalted butter and 1 cup of light brown sugar in a large bowl until creamy.

Add in 2 large eggs and 1 teaspoon of vanilla extract, continuing to mix until well combined.

Gradually add the dry ingredient mixture to the wet ingredients and mix on low speed until just incorporated. Fold in 2 cups of quick oats.

Press about 2/3 of the oatmeal mixture evenly into the prepared baking pan, creating a solid layer.

In a medium saucepan over medium heat, combine 1 cup of semi-sweet chocolate chips, 1 can of sweetened condensed milk, 2 tablespoons of unsalted butter, and ½ teaspoon vanilla extract. Stir continuously until smooth and melted.

Pour the fudge mixture over the pressed oatmeal cookie base in the baking pan and spread it evenly.

Crumble the remaining 1/3 of the oatmeal mixture over the fudge layer in clumps.

Preheat your oven to 350°F (175°C) and bake for 25–30 minutes, or until the top is golden brown.

Allow the bars to cool in the pan for at least 30 minutes before transferring them to a wire rack.