Make thick, homemade blueberry jam filling using fresh June blueberries for a visually striking donut reveal. This recipe focuses on simple steps for maximum flavor.
Combine blueberries, granulated sugar, and lemon juice in a small saucepan. Heat over medium heat, stirring occasionally, until the blueberries break down, about 10 minutes.
In a small bowl, mix cornstarch and water to create a slurry. Pour the slurry into the simmering blueberry mixture.
Cook, stirring constantly, until the jam thickens significantly, about 2 to 3 minutes. Remove from heat and let the jam cool completely. This is your fruit jam filling.
Prepare the donuts: Separate the refrigerated biscuit dough. Cut a hole in the center of each biscuit to form a donut shape.
Heat vegetable oil in a deep, heavy-bottomed pot or Dutch oven to 350 degrees Fahrenheit.
Carefully fry the donuts in batches, about 1 to 2 minutes per side, until golden brown. Remove with a slotted spoon and drain on paper towels.
Once the donuts are cool enough to handle, use a small knife or piping tip to poke a small hole in the side of each donut.
Fill a piping bag fitted with a long, narrow tip with the cooled blueberry jam. Gently pipe the thick jam filling into the center of each donut until it feels full.
Dust the filled donuts generously with powdered sugar before serving.
Notes
For the best jam consistency, ensure the cornstarch slurry is fully mixed before adding it to the fruit.
Maintain the oil temperature carefully; if it is too cool, the donuts will absorb too much oil.
This recipe uses store-bought dough for efficiency, making this a quicker summer baking project.