I'm sharing Dorie Greenspan's Pumpkin Whoopie Pies with Dulce de Leche filling for OXO's Bake a Difference campaign in support of Cookies for Kid's Cancer. Two soft, light pumpkin cookies studded with fresh cranberries are sandwiched with creamy dulce de leche marshmallow filling. I was contacted by OXO to participate in their Bake a Difference