In a large stock pot  heat oil over medium-high heat. Add the ham hock and sear all over to allow it to render some fat. Pour the water into the pot. Add the crushed red pepper. Reduce heat to medium-low and let simmer for 1 hour.

While the stock is simmering prepare the collard greens.

Wash the collard greens thoroughly. Remove the stems that run down the center by holding the leaf in your left hand and stripping the leaf down with your right hand. The tender young leaves in the heart of the collards don't need to be stripped. Stack 6 to 8 leaves on top of one another, roll up, and slice into 1/2 to 1-ince thick slices.

Add the collard greens to the water and ham hock mix a few handfuls at a time, stirring frequently to submerge the floaters.

Simmer slowly for one hour, adding more water if necessary. The greens should be a dark green and very tender.