Old-Fashioned Rolled Oats
Old-fashioned rolled oats are whole oat flakes that keep some shape and chew during cooking or baking. They work well when a recipe needs texture, body, and steady absorption.
Identity
Old-Fashioned Rolled Oats
Rolled flakes hold texture better than instant oats.
Use old-fashioned rolled oats when the flakes should stay visible and give a chewy, hearty texture. Quick oats absorb faster and turn softer, so they can change the texture of granola, cookies, and baked batters.
Wikimedia Commons
Reference image
Old-Fashioned Rolled Oats reference image.

Source: Wikimedia Commons
Used In Recipes
Substitutions
Acceptable
Old-Fashioned Rolled Oats -> Quick-Cooking Oats
1 ¾ cups old-fashioned oats or quick-cooking oats
The source lists this as an alternative in the same ingredient row.
Source: Easy No-Bake Granola Bars