In a small bowl, combine the first six ingredients. With clean hands, work butter into oat mixture until well combined. Refrigerate for 15 minutes., Place pears in a small bowl; add flour and toss to coat. Transfer to a greased 8-in. square baking dish; sprinkle with oat mixture. , Bake, uncovered, at 350° for 35-40 minutes or until topping is golden brown and fruit is tender. Serve warm, with ice cream if desired.