In a medium saucepan, combine fresh or frozen blueberries, lemon juice, and granulated sugar. Cook over medium heat, stirring gently until the sugar dissolves, about 3–4 minutes. Once the mixture reaches a gentle boil, reduce the heat and let it simmer for 10 minutes, stirring occasionally until it thickens slightly.

Remove the mixture from heat and cool to room temperature, about 30 minutes. Blend until smooth.

In a mixing bowl, combine the blueberry mixture, heavy whipping cream, and whole milk. Stir until fully combined.

Pour the mixture into your ice cream maker and churn according to manufacturer instructions for about 20–25 minutes.

Transfer the ice cream to freezer-safe containers, smooth the top, seal tightly, and freeze for at least 3 hours.