Place pecans in a nonstick skillet; coat pecans with cooking spray. Add brown sugar; cook over medium heat 3 minutes or until nuts are toasted and sugar melts, stirring occasionally. Remove from heat; cool. Combine sugared pecans and cracker crumbs in a small bowl; toss gently.
Arrange half of angel food cake slices in bottom of a 10-inch springform pan.
Combine pumpkin butter, cinnamon, and pumpkin pie spice in a small bowl. Place half of pumpkin butter mixture and half of ice cream in a food processor; pulse 12 times or just until blended. Spread pumpkin-ice cream mixture over cake layer in pan, and sprinkle with half of pecan mixture. Top with remaining cake slices; freeze 5 minutes.
Place remaining half of pumpkin butter mixture and remaining half of ice cream in food processor; pulse 12 times or just until blended. Spread pumpkin-ice cream mixture over cake layer in pan, and sprinkle with half of remaining pecan mixture. Cover and freeze 2 hours. Spread whipped topping evenly over cake, and sprinkle with remaining pecan mixture. Cover and freeze 8 hours or until firm. Let stand 5 minutes before serving. Run a knife around outside edge of dessert to loosen from pan; remove sides of pan. Drizzle with caramel topping.