Heat oven to 425 degrees. Spray a 3 quart baking dish with nonstick cooking spray.
In a bowl, combine the blueberries, jam, cornstarch, and 1/2 cup of sugar. Stir to coat. Pour the blueberry mixture into the baking dish. Top with 2 tablespoons of butter. Cook this mixture in the oven for 25 minutes until bubbly.
While the blueberries are cooking, prepare the dough. In a food processor, place the flour, baking powder, baking soda, salt, and 3 tablespoons of sugar. Pulse to combine. Add 6 tablespoons of butter to the food processor and pulse until the mixture is crumbly. This will be about 5 - 6 pulses.
Add the eggs, yogurt, lemon zest, lemon juice, and vanilla extract to the dough. Pulse until just starting to ball up and pull away from the sides.
When the blueberries are cooked, remove them from the oven and stir. Place the dough on top of the blueberries in spoonfuls across the top. Sprinkle the top with the remaining 1 tablespoon of sugar. Bake for 15 minutes until bubbly and light golden brown.
Serve Lemon Blueberry Cobbler with optional vanilla ice cream.