It turns out that onion skins contain quite a lot of dye that can apply a sort of marbled, golden-brown effect to your eggs. You can also use red onion skins, but the color that results isn't the rich magenta you expect—it's weirdly green actually. Scroll to the end to see what I mean. To color an egg in this way yourself, start with a sheet of aluminum foil, maybe a foot square. Make a sort of nest of onion skins in the middle of this, and place the egg in the middle; start trying to wrap the egg completely in several layers of skins. Your goal here is to leave no white showing.

Eggs bundled in red and yellow onion skins

Carefully hold the onion skin nest around the egg while forming the foil around it, to keep the skins where you put them. Again, leave no white showing as you close the foil completely. If you've got a whole family doing this and you want to identify yours later, sculpt the foil into a funny shape.

The ever-popular mohawk and pigtail styles

Optionally, try placing some masking materials on the egg surface before wrapping it in onion skins. Dill is a favorite; it tends to stick well to the egg if either is damp, and it leaves behind delicate dendrological patterns in white against the golden-brown color of the dyed egg.

Dill makes everything better.

Boil the foil packets in a pot of water for 10 minutes or so. A surprising amount of dye will leach into the water and turn it a tannic brown, so be careful draining this as it will probably stain your clothes.

Let cool, then unwrap your eggs! Try rubbing a bit of butter onto the surface to give them a nice sheen. The greenish-looking egg in the photo was wrapped entirely in red onion skins, which is a little less traditional (maybe for a reason!). Try this for yourselves next Easter, and let me know how it goes!