My grandma always dyed eggs with onion peels--that's how they did it back in the day! We made some last year but struggled with keeping the onion peel on the egg. This looks like an easier alternative.
60+ Easy and Beautiful Ways to Decorate Your Easter Eggs
Baking Powder Easter Eggs - see how we decorated this egg-ploding eggs. A fun way for kids to observe cause and effect and create colorful eggs I think I'll try this with food coloring vs powdered tempera paint.