Combine sugar and water in a small pot set over medium-low heat.
Constantly stir the sugar and water together as it gently heats until the sugar fully dissolves, about 2 minutes.
Add a cup of raspberries to the pot and frequently stir until the raspberries start to lose their form and release their juices into the water. This takes about 2 minutes.
Remove from heat and allow to cool for a few minutes.
Strain the raspberry simple syrup into a liquid measuring cup, mason jar, or other container.
Allow to cool a bit more and then add the simple syrup and lemonade to a large pitcher.
Mix well.
Measure out an ounce of both vodka and limoncello to add to a glass with some ice in it. Repeat for each glass you plan to serve.
Pour the raspberry lemonade into each waiting glass.
Serve as is or add garnishes such as raspberries, lemon wedges, or mint leaves.
Notes
You can add the alcohol directly to the pitcher. Multiply the number of servings by the vodka and limoncello serving amount. For example, you would add 8 ounces of vodka and 8 ounces of limoncello to the pitcher if you plan to serve 8 people.