1 1/4 cups pecan halves
1/2 cup all-purpose flour
1/2 cup packed brown sugar
1/2 stick cold butter, cut into pieces
2 1/2 tsp ground cinnamon
1 stick butter, softened
1 cup sugar
2 1/2 tsp baking powder
1/4 tsp salt
1 large egg
1 tbsp vanilla extract
2 1/4 cups all-purpose flour
1 cup milk
1 1/2 lb Granny Smith apples, peeled, cored, cut into 1/4-inch thick wedges
Powdered sugar for garnish, if desired
Preheat oven to 350 degrees. Lightly coat a 13 x 9-inch baking dish with nonstick cooking spray; set aside.
STREUSEL: Spread the pecans out on a rimmed baking sheet. Bake at 350 degrees for 8 to 10 minutes to toast. Stir once during the baking. When cooled, chop coarsely. In a medium bowl, using your fingers, mix together the flour, brown sugar, butter, and cinnamon until crumbly. Stir in the chopped pecans.
BATTER: Increase the oven temperature to 375 degrees.
In a large mixer bowl, with mixer on medium-high speed, beat the butter, sugar, baking powder, and salt until light and fluffy. Beat in the egg and vanilla until well blended. Add the flour in three additions alternating with the milk. Beat just to blend.
Spread 2 cups of the batter in the prepared pan. Sprinkle with half the streusel mixture. Top the streusel with the apple wedges; dot with the remaining batter. Sprinkle with the rest of the streusel.
Bake 40 to 45 minutes or until a wooden toothpick inserted near the center comes out clean. Remove pan to a wire rack to cool. Serve dusted with powdered sugar, if desired.