Part 1: Make the Blueberry Lavender Syrup
Simmer Berries: In the medium saucepan, combine the sugar, 1 cup of water, and the blueberries. Bring to a gentle simmer over medium heat, stirring until the sugar dissolves. Let it simmer for about 5 minutes as the blueberries burst.
Steep Lavender (Crucial Step): Remove the saucepan from the heat. Immediately stir in the dried culinary lavender.
Infuse: Cover the pot and let the lavender steep for 15-20 minutes. Do not steep for longer to avoid a bitter or "soapy" taste.
Strain: Pour the syrup through a fine-mesh sieve into a jar or bowl. Gently press the solids with a spoon to extract all the liquid. Discard the solids.
Chill Completely: Let the syrup cool to room temperature, then refrigerate until completely cold (at least 1-2 hours).
Part 2: Assemble the Lemonade
Combine: In a large pitcher, stir together the completely chilled blueberry lavender syrup and the freshly squeezed lemon juice.
Dilute: Pour in 4 cups of cold water (or sparkling water). Stir well.
Taste and Adjust: Taste the lemonade. If it's too strong, add more cold water (up to 2 more cups) until it reaches your desired strength.
Serve: Fill glasses with plenty of ice. Pour the lemonade over the ice. Garnish with a lemon wheel, a few blueberries, and a lavender sprig if desired.