Preheat oven to 350 degrees. Lightly butter a 9 x 13 inch baking pan. Stir pears with cranberries, sugar, flour, lemon rind, cinnamon and ginger. Place in prepared baking dish.
Using a fork, stir flour with oats and brown sugar. Drizzle butter over flour mixture and toss until mixture is crumbly.
Sprinkle evenly over fruit.
Bake for 55 to 60 minutes or until topping is golden and pears are tender.
Serve warm with a scoop of vanilla ice cream.