Cream butter and sugar until combined.
.Mix in the eggs and vanilla.
Mix the flour and baking soda together in a separate bowl.
Mix in the dry ingredients gradually until fully combined.
Mix in the red m&m’s.
Spread on a cookie sheet covered with parchment paper.Bake at 375 degrees for 10-15 min or until toothpick comes out clean.(Do not overbake!)
Once baked, set aside to cool completely.
While cookie bar cools start on the frosting.
Beat the butter on medium speed until smooth.
Add in the powdered sugar gradually mixing inbetween each addition.
Add in the heavy cream, vanilla extract, food coloring and continue mixing on medium-high speed for another minute or until everything is well combined, scraping down sides of bowl as needed.
Once bar is cooled and frosting is made, frost the cookie bar till totally covered.
Top with sprinkles you chose then serve and enjoy!