LINE 9x5-inch loaf pan with foil, extending over edges of pan. Combine cracker crumbs, ground pecans and 4 tablespoons melted butter in small bowl. Press firmly into bottom and halfway up sides of prepared pan.
WHIP heavy cream to stiff peaks in large bowl. Stir sweetened condensed milk, 1 cup chopped pecans, maple extract and 3 tablespoons melted butter in another large bowl until blended. Fold in whipped cream. Pour into prepared pan. Cover.
FREEZE 6 hours or until firm. Invert onto serving plate. Remove foil. Spoon caramel topping over loaf. Garnish with remaining 1/4 cup pecan halves. Slice into servings.
TIP*To toast nuts: Place nuts in dry nonstick skillet. Cook over medium heat, shaking pan until nuts are lightly browned. To avoid over browning remove from pan immediately.