In a small saucepan, add organic cane sugar, water, and dried lavender. Bring the mixture to a boil, stirring until sugar is dissolved. Simmer for 3 minutes. Remove from the heat and cover with a lid and let it steep for 15 minutes. After the time has elapsed uncover the saucepan and allow the simple syrup to cool for 15 minutes. After the syrup has cooled, strain it through a fine mesh strainer, pushing the lavender with the back of a spoon to squeeze out all of the syrup.
In a blender, combine hulled and sliced strawberries with the ½ cup of water. Blend until strawberries are fully puréed. Strain the purée through a fine mesh strainer, pushing with a spoon to try to get as much of the purée through the strainer without the seeds going through.
Squeeze the lemons using a citrus reamer, electric citrus juicer, or by hand.
In a large pitcher, add the strawberry purée, then add the lemon juice, the lavender simple syrup, vanilla extract, water, and sparkling water. Stir to combine. Pour over ice-filled glasses and serve with a lemon slice and strawberry, if desired.