Instant Oats have been pre-cooked and dried, allowing them to cook in about a minute. Quick Oats are processed in smaller pieces that cook in less the 5 minutes. ROGERS Large Flake Oats are less processed oats.  They cook 7 to 10 minutes on the stove top and about 2 to 3 minutes in the microwave. Steel Cut oats are cut with a steel blade into coarse pieces.  They take about 45 minutes to cook.