Preheat the oven to 350°F (175°C). Grease or line a 9×13-inch baking pan with parchment paper, leaving an overhang for easy removal.
In a large bowl, whisk together the melted butter and brown sugar until smooth and combined.
Add the eggs and vanilla extract, mixing well.
In a separate bowl, sift together the flour, baking powder, and salt. Gradually add to the wet ingredients, stirring until just combined.
Fold in the oats, then gently stir in the chocolate chips and caramel bits, saving a small handful of each for topping.
Press half of the batter evenly into the prepared pan. Sprinkle the reserved chocolate chips and caramel bits evenly over this layer.
Crumble the remaining batter on top to form the second layer.
Bake for 30-35 minutes, or until golden brown and caramel is bubbling.
Let cool completely in the pan before slicing into bars.