Preheat the oven to 350 degrees. Spray a 13 x 9 pan with cooking spray and set aside.

In a large bowl cream the butter, brown sugar, and granulated sugar.

Beat in the eggs Add the vanilla and stir well.

In a medium bowl combine the flour, oats, salt, and baking soda. Add the flour mixture to the sugar mixture and stir with a fork until it is crumbly.

Place 3 cups of the oat mixture on the bottom of the pan pressing into the bottom.

In a microwave safe bowl heat the sweetened condensed milk and butterscotch chips. Microwave for 45 seconds and stir. Continue heating at 15 second intervals until the mixture is completely melted and mixed well. Pour the butterscotch mixture over top of the oat crust and spread.

Sprinkle the top with the remaining oat mixture.

Bake for 30-35 minutes or until butterscotch is bubbling and the topping in a light brown. Put the entire baking pan on a wire rack to cool. Cut into 24 bars.