Create a simple syrup by combining 1 cup water and sugar in a small saucepan. If using fresh or dried lavender add that to your saucepan.
Bring to a simmer and cook, stirring until sugar is dissolved. Let cool to room temperature.
Using a fine mesh strainer, strain lavender from the simple syrup.
Combine lemon juice, simple syrup, and water in a 1 quart pitcher. If using extract, add 2 drops of lavender oil.
Add food coloring if desired.
Serve with ice and lemon slices.
