1. Preheat oven to 400°.
2. Weigh or lightly spoon flours into dry measuring cups; level with a knife. Place oats in a food processor; process until finely ground. Add flours, brown sugar, and next 5 ingredients (through allspice) to processor; pulse 3 times. Add butter; pulse 5 times or until mixture resembles coarse meal. Add sour cream and vanilla; pulse 3 times or just until combined (do not overmix). Add cherries and nuts; pulse 2 times.
3. Turn dough out onto a lightly floured surface; knead lightly 3 times. Roll dough to a 1/2-inch thickness; cut with a 2 1/2-inch biscuit cutter to form 10 rounds. Place rounds 1 inch apart on a baking sheet lightly coated with cooking spray. Bake at 400° for 14 minutes or until golden brown. Remove from baking sheet; cool on a wire rack.
4. Combine powdered sugar and 4 teaspoons milk, stirring with a whisk. Drizzle powdered sugar glaze over scones.