Make the thyme simple syrup first. Mix water and sugar in a small saucepan over medium heat. Stir until sugar dissolves.
Then, add thyme sprigs and simmer for 5 minutes.
Remove from heat and let steep for 15 minutes. Then, strain and cool to room temperature.
Add 2-3 thyme sprigs to the shaker and muddle gently to release oils.
Next, pour in lemon juice and thyme simple syrup.
Fill the shaker with ice and shake for 10-15 seconds.
Then, double strain into an ice-filled glass.
Top with tonic water and stir gently. Garnish with a lemon wheel and fresh thyme sprig.
Notes
The thyme simple syrup stays fresh in the refrigerator for up to 2 weeks.For a stronger thyme flavor, steep the herbs longer in the simple syrup.Replace regular tonic water with flavored varieties like elderflower or cucumber for different taste combinations.Make a big batch of the base mixture (minus tonic water) for parties. Add tonic water individually when serving.