Preheat oven to 375°F. Line a large baking sheet with parchment paper and set aside.

In a medium saucepan, melt the butter over medium-low heat. Once melted, remove from the heat and stir in the oats, sugar, salt, corn syrup, milk, vanilla, and flour until combined.

Scoop out tablespoon sized portions of the mixture and place on the prepared baking sheet 3 inches apart. The cookies will spread during baking.

Bake for 8 minutes, or until golden brown. Allow the cookies to cool slightly on the baking sheet (3-4 minutes) and then transfer to a wire rack to cool completely.

In a microwave safe bowl, melt the chocolate chips in 25 second increments, stirring after each, until melted and smooth.

Spread a layer of the milk chocolate on the bottom of half the cookies, and then press another cookie on top of the melted chocolate, creating a sandwich. Allow the chocolate to set.