1.Cut the beet tops into bite-sized pieces. Focus especially on the stems, because the leaves will shrink significantly during cooking so their size is less important.
2.Rinse chopped beet tops thoroughly.
3. Pour slightly more olive oil into the saucepan than is needed to cover the bottom.
4. Slice the garlic into very thin slices and place in the saucepan.
5. Add a pinch of chili flakes. Don’t go overboard now; you can always add more later if you want the dish to be spicier.
6. Saute garlic and chili flakes over low to medium heat until garlic is translucent and tender, but not brown. Stir frequently with wooden spoon to prevent burning or sticking.
7. Add the beet tops along with a generous pinch of salt. Stir the mixture until the beet tops are evenly coated in the olive oil.
8. Cook the beet tops for five to 10 minutes, stirring frequently, over low to medium heat. After five minutes, try a piece of stem. The beet tops are done when the stems are tender, but still slightly firm.
From ehow.com (how to cook beet greens)