Heat oven to 325°F. In ungreased 8-inch square or 11x7-inch (2-quart) glass baking dish, arrange pears and peaches. In medium bowl, beat eggs with wire whisk until blended. Beat in 1/4 cup flour, the granulated sugar, sour cream and vanilla until smooth. Pour over fruit in baking dish.
In small bowl, mix all topping ingredients until crumbly. Sprinkle over fruit mixture.
Bake 30 to 40 minutes or until topping is golden brown and center is set. Cool at least 15 minutes. Serve warm with ice cream. Cover and refrigerate any remaining custard.