Extract juice from fresh chokecherries and measure 2 cups of chokecherry juice.

In a mixing bowl, whisk together 1/2 cup granulated sugar, 1/4 cup cornstarch, and 1/4 teaspoon salt.

Heat 2 cups of milk in a medium saucepan over medium heat until warm, about 5 minutes.

Stir the chokecherry juice into the warm milk in the saucepan.

Gradually whisk in the sugar and cornstarch mixture into the saucepan to prevent lumps.

Continue cooking over medium heat, stirring constantly, until the mixture thickens, about 5 to 7 minutes.

Remove from heat and stir in 1 teaspoon vanilla extract and 1 tablespoon butter until fully combined.

Pour the pudding into serving bowls and refrigerate for at least 2 hours to set before serving.