Remove the peels from the lemons and trim off any excess white pit.
Place the lemon peels and 60% proof vodka in a mason jar. Fridge for 5 days.
On the 5th day, prepare your sugar syrup. In a small saucepan, mix sugar and water together and bring to a light boil. Cook, stirring, for 5 minutes until the sugar is completely dissolved. Remove the sugar syrup from the heat and let cool to room temperature.
Strain the alcohol and lemon peels into a measuring cup and note how much liquid has remained, it should be about 1 1/2 cups of alcohol. Using a funnel, pour the alcohol into a corkable bottle.
Next, measure out the same amount of simple syrup into measuring cup. Slowly add the simple syrup to the limoncello but stop about halfway and give it a sample. If it's too strong, add more syrup. I ended up using about 75% of the simple syrup. You can always add more but you can't take away if it's too sweet. Bottle and enjoy!
TIP: If you want to jazz up your limoncello, you can optionally add lavender or fresh thyme to infuse in the simple syrup before adding it to the alcohol.