In a medium bowl, combine rolled oats, brown sugar, flour, cinnamon or nutmeg, and salt; add butter, mixing well. Set aside.
Arrange apple slices in an 8 x 8 x 2-inch or 9 x 9 x 2-inch baking dish/pan lightly coated with non-caloric vegetable cooking spray. Evenly sprinkle butterscotch flavoring over apples, if desired. Evenly sprinkle oat mixture over fruit. Evenly sprinkle nuts and coconut over oat mixture.
Bake in a preheated hot oven (400 degrees F.) for 25 to 30 minutes, or until topping is golden brown and crisp and fruit mixture is bubbly hot. To serve, spoon warm or room temperature Butterscotch Apple Crisp into dessert dishes, dividing evenly. Top each with a scoop of vanilla ice cream or a dollop of sweetened flavored whipped cream or other whipped topping, if desired.
Note: May reduce butter to 1/3 cup, if desired; however, topping will not be as rich in flavor or texture.
Variations: Omit apples and use 3 to 4 firm ripe medium to large pears (Bartlett, Anjou, or Bosc variety pears).
Add ½ cup chopped crystallized ginger to nut or fruit mixture.