In a medium saucepan, combine the blueberries, sugar, orange zest, and 1 tablespoon of the orange juice.

Cook over medium heat, stirring frequently, until the berries burst and the mixture becomes thick and jammy, about 8 to 10 minutes.

In a small bowl, whisk the cornstarch into the remaining 2 tablespoons of orange juice until smooth.

Slowly pour the cornstarch mixture into the bubbling jam, stirring constantly. Cook for 1 to 2 more minutes, until the jam thickens to your liking.

Remove from heat and transfer to a heat-safe bowl or jar. Let cool to room temperature, then cover and refrigerate.