Preheat the oven to 350 degrees F. Melt both sugars and the butter together until the brown sugar is mostly melted. (You can do this in the microwave for 2-3 minutes or on stovetop.)
Mix the flour, baking soda, baking powder, salt and lemon zest together. Add the melted sugar mixture and stir. Then add the eggs and vanilla. Stir well.
Press the mixture into a greased 9 X 13 inch baking dish. Sprinkle the white chocolate chips over the top. Then toss the blueberries with 1 tablespoon of flour and sprinkle them over the top.
Bake for 45-55 minutes, until a toothpick inserted into the middle comes out clean. If the edges of the blondies start to get dark, loosely tent a piece of foil over the top of the pan. Cool to room temperature before cutting.