"The Best Pot Roast....EVER!" - McCormicks slow cooker Savory Pot Roast season packet - Au Jus packet - 1 can of Pepsi or Coke - 3.5 lbs Boneless Cross Rib Roast Put Roast in the crock pot. Mix the Slow cooker seasoning with 1 cup of Water. Pour on top of roast. Add the whole can of Coke. Cover with your lid for 8 Low or 4 hours on high. Right before you are ready to pull it out, sprinkle your dry Au Jus packet over the roast. Remove meat and slice.