Fall Plum and Walnut Crisp

For Topping:

Combine walnuts, flour, brown sugar, cinnamon, ginger, salt and nutmeg in a food processor. Pulse to blend. Add butter and blend until moist clumps form. Transfer topping to a medium bowl. Cover and refrigerate 20 minutes.

For Filling:

Preheat oven to 400 degrees. Toss together plums, sugar, cornstarch and vanilla in a large bowl. Let fruit mixture stand 5 minutes, tossing occasionally. Transfer filling to an 11x7 inch baking dish. Crumble topping evenly over fruit. Bake about 40 minutes until filling is bubbly and topping is dark golden. Transfer crisp to a rack and let cool 30 minutes before serving. Serve warm with ice cream if desired.