Preheat oven to 375°F and grease a 9x9 baking pan.
In a medium bowl, stir together oats, pecans, brown sugar, salt,cinnamon, nutmeg, allspice and baking powder. Set aside.
In a second medium bowl, whisk together egg, vanilla, milk, and butter.
Place dry ingredients and frozen blueberries in baking pan, gently stirring berries into mixture.
Pour liquid ingredients over oats and berries. Let liquid begin to set into dry ingredients for about 1 minute then bake for 35-40 minutes or until center is set and top is slightly golden brown.
Serve warm or cold with toppings as desired.