Melt 1 1/4 cups of unsalted butter in a microwave-safe bowl for about 30 seconds until fully liquid.

Combine melted butter with quick oats, all-purpose flour, and soft brown sugar in a large mixing bowl.

Press two-thirds of the mixture into the bottom of a greased 9x13 inch pan. Bake at 325°F for 10 minutes.

In a saucepan, combine 1/4 cup butter and 1 cup brown sugar over medium heat, stirring continuously until smooth and bubbly (3-4 minutes).

Gradually stir in 1/4 cup milk and vanilla extract, mixing until well incorporated and smooth.

Bring the caramel mixture to a gentle boil, stirring constantly for about 3 minutes until thickened.

Pour the hot caramel filling over the cooled crust and sprinkle with the reserved crumb mixture.

Bake at 300°F for 20 minutes until the topping is golden.

Allow the bars to cool completely before cutting into squares.