Preheat oven to 350°.
Lightly spoon flours into dry measuring cups, and level with a knife. Combine flours, oats, sugar, butter, and nutmeg in a food processor; pulse 5 times or until mixture resembles coarse meal.
Press two-thirds of oat mixture into bottom of an 8-inch square baking pan coated with cooking spray. Bake at 350° for 10 minutes. Spread preserves over warm crust. Sprinkle with remaining oat mixture, and press gently. Bake for an additional 25 minutes or until lightly browned and bubbly. Cool completely in pan on a wire rack.