Here's a PSA from Serious Eats: Don't throw out your leftover lemon rinds. Save them to make sweet, citrusy syrup perfect for adding to baked goods. Image from Serious Eats.
Add a few cups of sugar to lemon rinds, and the sugar will dissolve completely, leaving behind "liquid sunshine". You can even crush the rinds further to get more juice out of them.
What can you do with this? As Stella Parks notes:
Since then, I've discovered that fresh lemon syrup is a fantastic addition to homemade granola, a replacement for cream in white chocolate ganache, a complement to sweet tea, and a worthy part of almost any sorbet. Because the syrup is never boiled to dissolve the sugar or reduce the juice, it doesn't take on any of that slow-cook funk that ruins so many fruity desserts. Its flavour stays pure and clean, adding a burst of lemony sweetness to everything from marinades to cocktails and candied pistachios, without ever watering them down.
A little should go a long way, and you'll be able to use up every last bit of the lemons you've bought.