Cook 6 eggs in boiling water for seven minutes. Let cool and peel.
Clean, peel, and slice the beets.
Pickling Liquid: In a medium saucepan, add 4 cups water, the beet slices, 1/2 cup lemon juice or vinegar, 1 tsp. salt. Bring to a boil, then reduce heat to simmer for 30 minutes. Let cool.
Transfer the pickling liquid to a large resealable bag and set the bag in a large bowl, add 6 peeled hard-cooked eggs.
Squeeze the air out of the bag and seal. Make sure the eggs are submerged in the pickling liquid.
Refrigerate for 5 hours.
Remove the eggs from the liquid and blot dry with a paper towel.
Cut one cooked beet into fine dices and set aside to be used for garnish.
Cut your dyed eggs in half and remove the egg yolk.
Prepare the filling: In a small bowl add the egg yolk, mayonnaise (or yogurt), half of the feta, salt, and pepper. Mix well.
Tear small pieces of lettuce to be placed into the egg half.
Pipe or spoon the filling on top of the lettuce leaf in the egg half.
Garnish with chopped beets, green onions, remaining feta, and two pumpkin seeds.