Then add the blueberries, sugar, vanilla, and lemon juice. Stir and set aside.
Topping
Preheat the oven to 375°F.
In a medium bowl, mix the flour, baking powder, and salt. Set aside.
In a mixing bowl, beat the butter and sugar until creamy.
Beat in the egg and vanilla extract until just blended.
Add the flour mixture a little at a time until all the flour is added. Beat until just combined.
Spoon the topping dough over the blueberries.
Bake for 30-40 minutes or until lightly browned. Check the middle of the cobbler for any uncooked crust by sticking a spoon into it. If there is any uncooked crust, place a sheet of aluminum foil over the pie and return it to the oven for 5 to 10 minutes or until the middle is cooked. The aluminum foil will help prevent the crust from over-browning.
Notes
Aluminum Foil
If the cobbler starts to over-brown before the initial cooking time is finished, place a sheet of aluminum foil over it while it finishes baking.