Add 2/3 cup ground decaf + 1 1/3 cup ground caffeinated coffee + 1 1/2 cup room temperature water in a bowl.
Stir well and scrape edges of coffee down into liquid.
Cover with plastic wrap and let sit for 24 hours at room temperature.
Strain entirety through mesh strainer with a large coffee filter (may drip up to 45 minutes). Discard grounds and refrigerate coffee.
Mix 1/4 cup coffee brewed previously + 1/2 cup cold water + 2 tablespoons coffee mate creamer in drinking glass.
Add iced cubes to fill glass and Enjoy!