Preheat the oven to 350°F (175°C). Lightly butter the bottom and sides of a 9x13-inch metal baking pan. Line the bottom with parchment paper, allowing the paper to extend up two opposite sides for easy removal. Butter the parchment paper as well.

In a medium mixing bowl, whisk together the flour, salt, and baking soda. Add the dark brown sugar and use your fingers to incorporate it into the flour mixture until combined and crumbly. Stir in the rolled oats. Create a well in the center of the dry ingredients and pour in the melted butter. Stir until the mixture is thoroughly moistened.

Spread two-thirds of the oatmeal mixture evenly into the prepared baking pan, pressing down gently to form a firm base. Bake for 10 minutes. Remove from the oven and place on a wire rack to cool slightly while preparing the caramel filling.

In a medium saucepan over medium-high heat, melt the light brown sugar and cubed butter together, stirring constantly. Once the mixture reaches a boil, continue boiling for 1 minute, stirring continuously to prevent burning. Remove the pan from heat and stir in the heavy cream and vanilla extract until smooth.

Evenly sprinkle the chopped pecans and chocolate chips over the slightly cooled oatmeal crust. Carefully pour the warm caramel mixture over the pecan and chocolate layer. Use an offset spatula to spread the caramel evenly across the surface. Sprinkle the remaining oatmeal mixture evenly over the top.

Return the pan to the oven and bake for an additional 10 to 12 minutes, or until the top is golden brown.

Allow the bars to cool in the pan on a wire rack for 15 minutes. Transfer the pan to the refrigerator and chill for approximately 1 hour, or until fully set. Lift the bars out of the pan using the parchment overhang, cut into squares, and serve.