Lightly coat a 9x5x3-inch loaf pan with nonstick cooking spray. Spread half of the macaroon crumbs on bottom of pan.
In a blender container, cover and blend enough of the peaches to measure 2 cups puree (mixture should be slightly chunky). Combine peach puree, sugar, and lemon juice. Add almond extract, if you like. Fold in whipped cream. Pour mixture over the crumbs in loaf pan and top with remaining crumbs.
Cover and freeze about 6 hours or until solid. Makes 10 servings.
You can store this in your freezer for up to 2 weeks.