Apple Snickerdoodle Dump Cake

6 cups sliced, peeled tart apple (about 8 medium)
1/3 cup packed brown sugar
1/4 cup sugar
1/4 cup orange juice
1 tablespoon lemon juice
1 package (17.9 ounces) snickerdoodle cookie mix
1/2 cup butter, melted
1 cup coarsely chopped pecans or walnuts
Whipped cream, optional

Preheat oven to 350°. Toss apples with sugars and fruit juices; spread into a greased 11x7-in. baking dish.
Place cookie mix in a bowl; stir in contents of cinnamon-sugar packet. Sprinkle over apples. Drizzle with butter. Top with pecans.
Bake until golden brown and apples are tender, 35-40 minutes. Serve warm and if desired, top with whipped cream.