Spiked Blueberry Crumb Bars

Why I Love This Recipe
This was the second time in a week that I had baked with rum. I couldn't help myself. The bottle was sitting on the counter, calling my name. It's voice sounded suspiciously like Captain Jack Sparrow's, which mine could start sounding like after a few more of these recipes. The original inspiration for these bars came from the fabulous Smitten Kitchen. However, she did not have to contend with any talking bottles.
Ingredients You'll Need
4 cups fresh blueberries
3 tbsp dark rum (or 3 tbsp fresh lemon juice)
1 cup granulated sugar, divided
4 tsp cornstarch
1/2 cup packed brown sugar
3 cups flour
1 tsp baking powder
1/4 tsp salt
1/2 tsp ground ginger
1/2 tsp ground nutmeg
1 cup (8 oz) cold butter
Directions
Preheat the oven to 375 degrees F. Grease a 9x13 inch baking pan.
In a medium bowl, combine the fresh blueberries and dark rum (or lemon juice).
Stir in 1/2 cup granulated sugar and 4 tsp cornstarch. Set aside.
In a separate medium bowl, combine 1/2 cup each of granulated sugar and brown sugar.
Stir in flour, baking powder, salt, ground ginger, and ground nutmeg.
Cut in cold butter with a pastry cutter or a fork until the mixture is crumbly.
Whisk one egg in a small bowl and stir into the flour mixture.
Press half of the flour mixture into the bottom of the prepared pan.
Spread the blueberry mixture over the crust.
Sprinkle the rest of the flour mixture over the blueberries.
Bake in the preheated oven for 40-45 minutes, or until the top is light brown.
Let the bars cool on a rack and then place the fridge to chill. This will make the bars easier to cut and remove from the pan.