In a saucepan, combine blueberries, sugar, and 1 cup of water.

Cook over medium heat for 5–7 minutes until blueberries soften and release juices.

Remove from heat and let the mixture cool slightly.

Blend the mixture until smooth.

Strain through a fine mesh sieve to remove skins (optional).

In a large pitcher, combine blueberry mixture, lemon juice, and remaining water.

Stir well and adjust sweetness if needed.

Add ice and chill for 10–15 minutes.

Serve in glasses with lemon slices and fresh blueberries.