Combine first 3 ingredients in a large bowl, stirring to coat apples.
Melt butter in a large skillet over medium-high heat. Add apple mixture; bring to a boil, and cook, stirring often, 10 minutes. Add pears to skillet, and cook, stirring often, 5 minutes. Spoon hot fruit mixture into a lightly greased 10-inch (8-cup) deep-dish pie plate or shallow 2-quart baking dish. Spoon Oatmeal Muffin Batter evenly over fruit mixture.
Bake at 425° for 20 to 25 minutes or until crust is golden brown. Garnish, if desired.
*2 (21-ounce) cans apple pie filling can be substituted for apples and pears. Omit brown sugar and flour. Melt butter in a large skillet over medium-high heat. Add pie filling, and bring to a boil; remove from heat. Proceed with recipe as directed.