Coffee Frosting for Brownies

I saw this recipe for Mocha Brownies from browneyedbaker.com but I have to say the older I get the easier I try to make things. She has the recipe for the brownies and for the frosting but I decided to buy a box fudge brownie and just use her frosting recipe. Her recipe only made an 8 x 8 dish of brownies but I bought a family size mix and used my dish that is slightly smaller than a 13 x 9 pan. I baked the brownies according to the box directions. I didn't double the frosting because I don't think brownies need much frosting. I made a few changes, it calls for 1 1/2 teaspoon of heavy cream but I didn't have any so I used milk and I didn't have espresso so I used Folgers instant coffee. Next time I need a dessert I will be making these again, I love the coffee/chocolate taste!
Frosting
1 teaspoon of vanilla
1 teaspoon of instant coffee
1/2 cup of soft Parkay butter
1 1/4 cup of powdered sugar
1 1/2 teaspoon of milk
Mix the vanilla and coffee and set aside. On medium high whip the butter. Reduce the speed to low and add the powdered sugar slowly. Once all of the powdered sugar is mixed in set the speed to medium high and beat 2 more minutes. Add coffee and vanilla. Add the milk. I found the frosting a bit to thin so I added more powered sugar and beat a minute more. Spread over brownies and enjoy.