There are many ways to prepare collards. The first method calls for removing and discarding the stem and center ribs. Then cut leaves into one inch pieces. In a kettle of boiling water cook for 15 minutes. Drain into a colander, pressing out extra water with the back of a spoon. In a 12 inch skillet add minced garlic ( to your taste) to 1 TBL of butter and 1 TBL of olive oil. Saute until heated through about 5 minutes. Be careful that the garlic does not burn.
In the second method blanch the collards briefly 1-2 minutes, then plunge into cold water to stop the cooking process. Continue as above.
The third method and the one I prefer skips the boiling water. Remove the stems but not the ribs, Stack the collards, then roll as you would sushi. Chop vertically so that you end up with ribbons. Saute in butter and olive oil adding garlic to your taste.. I also add a bit of miso mixed with water to get the salty flavor I like.