01 -
Preheat oven to 350°F. Grease a 9x13-inch baking pan with non-stick spray or line with parchment paper leaving an overhang for easy removal.
02 -
Using a stand mixer fitted with a paddle attachment or a hand mixer, beat unsalted butter and granulated sugar together until smooth and fluffy. Add eggs and vanilla extract; mix thoroughly, scraping down the bowl as needed.
03 -
In a separate bowl, sift together unsweetened cocoa powder, all-purpose flour, and salt.
04 -
Gradually add dry ingredients and milk alternately to the butter mixture, starting and ending with dry ingredients. Mix on low speed until just combined.
05 -
Pour batter evenly into prepared pan and bake for 30 minutes. Allow to cool for 20–30 minutes, keeping brownies slightly warm for frosting application.
06 -
In a saucepan over medium-high heat, combine unsalted butter, milk, and granulated sugar. Bring to a boil and continue boiling for one minute. Remove from heat; whisk in salt and milk chocolate chips until smooth.
07 -
Immediately pour frosting over warm brownies and spread evenly using an offset spatula before the frosting sets. Allow to set for at least one hour before slicing.