First make simple syrup for lemonade. Combine the lemon peel and sugar into a pot with 1 quart of water. Bring to a boil and then simmer for 5 minutes, stirring occasionally until the sugar is dissolved.
Remove from heat and strain to remove the lemon peel.
While the simple syrup is hot, add the saffron and let it steep 5-10 minutes.
In a serving pitcher, combine an additional 3 quarts of water, lemon juice and the saffron syrup and stir until mixed. Garnish with thinly sliced lemons.