We like to use whole wheat pastry flour because it adds color and texture, but all-purpose flour also works.
Preheat oven to 375°.
To prepare crust, lightly spoon 1/2 cup whole wheat pastry flour and 1/2 cup all-purpose flour into dry measuring cups; level with a knife. Combine flours and next 3 ingredients (through 1/8 teaspoon salt) in a bowl; cut in butter with a pastry blender or 2 knives until mixture resembles coarse meal. Sprinkle surface with ice water, 1 tablespoon at a time, tossing with a fork until moist and crumbly (do not form a ball). Press mixture gently into a 4-inch circle on plastic wrap. Cover and chill 5 minutes in freezer. Slightly overlap 2 sheets plastic wrap on a slightly damp surface. Unwrap and place chilled dough on plastic wrap. Cover dough with 2 additional sheets of overlapping plastic wrap. Roll dough, still covered, into a 10-inch circle (A). Place dough in freezer 5 minutes or until plastic wrap can be easily removed. Remove top sheets plastic wrap; fit dough, plastic wrap side up, into a 9-inch round removable-bottom tart pan coated with cooking spray. Remove remaining plastic wrap (B). Fold edges under; flute. Cover and refrigerate.
To prepare filling, place apple in a large bowl. Sprinkle with cornstarch; toss well to coat. Stir in brown sugar and next 3 ingredients (through cinnamon).
To prepare topping, lightly spoon 1/4 cup whole wheat pastry flour and 1/3 cup all-purpose flour into dry measuring cups; level with a knife. Combine flours, 3 tablespoons sugar, baking powder, and dash of salt; drizzle with melted butter. Toss with a fork just until combined (mixture will be lumpy).
Spread apple mixture in crust; sprinkle evenly with topping. Bake at 375° for 50 minutes or until fruit bubbles and topping is golden brown. Cool in pan to room temperature on wire rack.
Note: Nutritional analysis includes Maple Ice Milk.