Stir together 1/3 cup sugar with water, lemon juice, and cornstarch in a small saucepan, the stir in blueberries. Bring to a simmer, then simmer, stirring occasionally for 3 minutes. Remove from heat.
Whisk together flour, baking powder, salt and remaining 1/2 cup sugar in a medium bowl.
Whisk together egg, milk, butter and vanilla in a large bowl, then add flour mixture, whisking until just combined.
Spoon batter into baking pan, spreading evenly, then pour blueberry mixture evenly over batter (berries will sink). Bake until a knife inserted into center of cake portion comes out clean, 25 to 30 minutes. Cool in pan on rack for 5 minutes.
Submitted By: Kyle
Makes a fabulous dessert or breakfast cake!!
Rachel - LOVE THIS!!! I am going to send it to work with my sweetie tomorrow for a nice treat for him and his co-workers. My only suggestion/comment would be to add something that can distinguish it from blueberry pancakes- it tastes very similar!