Make the Blueberry Lavender Syrup
Combine 1/2 cup fresh blueberries, 1 tbsp dried culinary lavender, 1/4 cup agave syrup, and 1/2 cup water in a small saucepan.
Bring the mixture to a gentle boil over medium heat, then lower the heat to a simmer. Let it simmer for 5–7 minutes, until the blueberries burst and the syrup thickens slightly.
Remove the pan from heat and let the syrup cool for about 10 minutes. Strain the syrup through a fine sieve into a bowl or measuring cup, pressing the solids to extract flavor. Discard solids (or save them to top yogurt — no waste!). Chill the syrup in the fridge if you want it to get colder faster.
Prepare the lemonade base
Squeeze juice of 2–3 lemons to yield roughly 1/2 cup lemon juice. I usually aim for 2 big lemons and taste; add the third if it needs more brightness.
Pour the lemon juice into a pitcher and add the cooled blueberry lavender syrup. Stir to combine.
Assemble the fizz
Fill each glass with ice cubes.
Add 2–3 tbsp of the lemon + blueberry lavender mixture per glass (adjust to sweet or tart preference).
Top with sparkling water until the glass is nearly full. Stir gently to marry flavors.
Garnish and serve
Garnish with a sprig of lavender and a lemon slice. Add a few fresh blueberries into the glass for that jewel-like look.
Serve immediately and enjoy the fizzy, floral refreshment.
Pro tip: If you like stronger floral notes, use a little more lavender in the syrup — but don’t overdo it. Lavender goes from charming to soapy very quickly.