1. Heat oven to 375 degrees F. Coat sides of 9 x 9 x 2-inch-square cake pan with nonstick cooking spray. Place 3 tablespoons butter in bottom of pan; swirl to coat bottom. Sprinkle with 1/3 cup brown sugar and 1/4 teaspoon spice. Arrange 12 pecan halves if using around perimeter of pan. Arrange apple slices in pan. Chop remaining pecans.
2. Stir together flour, baking soda, salt and remaining spice in medium-size bowl until combined. Beat together remaining butter and brown sugar in medium-size bowl until smooth. Stir in 3/4 cup water. Stir in flour mixture and chopped nuts just until combined. Spoon into pan evenly over apples.
3. Bake in 375 degrees F oven for 30 minutes or until wooden pick inserted in center comes out clean. Let cool on rack for 10 minutes. Invert onto serving plate; remove pan. Serve warm.