In a large saucepan, combine the rhubarb, sugar, lemon zest, vanilla and 3 1/2 cups water. Set over medium-high heat and bring to a boil. Reduce heat to low, cover and cook until the sugar has dissolved and the rhubarb has just begun to soften, about 8 minutes. Add in the sliced strawberries, cover and continue to cook for another 4 minutes to soften those as well. Uncover, remove from heat and let cool to room temperature.

Pour the strawberry rhubarb simple syrup into a large pitcher, through a fine-mesh sieve. Use a wooden spoon to squeeze all the juice out of the pulp, and discard any leftovers in the sieve.

Stir in the fresh lemon juice to the pitcher and about 1 to 1 1/2 cups water until the desired sweetness/tartness is reached. Refrigerate until ready to serve.

Fill glasses with lots of ice and pour in about an ounce of gin or vodka to each glass. Then top off with the lemonade. Garnish with lemon slices, mint or small strawberries. Enjoy!