Step 1

Preheat oven to 350°F and spray a 9x13" pan with cooking spray.

Step 2

Mix the boxed brownies according to package instructions and spread into prepared pan.

Step 3

Bake for 15 minutes (they'll still be soft at this point).

Step 4

While the brownies are baking, combine the chocolate chips and sweetened condensed milk in a microwave-safe bowl.

Step 5

Microwave on high for 60 seconds, stirring halfway through. If the chocolate chips aren't completely melted, add a little more time until it's smooth.

Step 6

Drizzle over the brownies and carefully spread with the back of a spoon.

Step 7

Sprinkle toffee bits on top.

Step 8

Bake an additional 18-20 minutes.

Step 9

Let cool completely before cutting.