Shake vigorously for about 15 seconds until well chilled.
Strain into the prepared glass over fresh ice.
Garnish with a lemon wheel or a small lavender sprig. Serve immediately.
Notes
Use tequila blanco for a clean profile; swap in reposado for a warmer, vanilla note. Fresh lemon juice is essential. Make lavender syrup by simmering equal parts sugar and water with culinary lavender, then straining and chilling.