Preheat oven to 350 degrees F.  Butter a 9 by 13 inch baking pan.  Sprinkle the pecans on the bottom of the pan.

In a large bowl, stir together flour, sugar, and baking powder.  Stir in the butter, eggs, and milk until a batter forms.  Fold in the blueberries and pour on top of the pecans in the pan.  Bake for 1 hour to 1 hour and 20 minutes, until golden brown and a toothpick inserted in the center comes out clean or with a few moist crumbs.  Serve warm or cool completely in the pan.  Cake may be stored in an airtight container at room temperature for up to 5 days or in the freezer, wrapped in pieces in parchment and foil and placed in a zipper bag for up to 3 months.  Thaw at room temperature about an hour or in the microwave about 1 minute.