Preheat the oven to 350 °. Line a 9x13 baking pan with parchment paper.
In a large mixing bowl, combine the sugar and oil. Mix in the egg and vanilla until smooth.
Add the flour, baking powder, cinnamon, nutmeg, and salt. Blend just until mixed. Spread into the prepared pan. The dough will be fairly thick and appear a little greasy.
In a small bowl, combine the topping ingredients and sprinkle them over the batter.
Bake for 20 to 25 minutes or until crisp. Allow the dish to set for about 10 minutes before removing the entire piece, holding onto the edges of the parchment, and placing it on a wire rack to cool completely. Slice into squares and serve. Store cookies in an airtight container for up to a week.
Notes
To freeze: Layer the squares between pieces of parchment in an airtight container or wrap each individually in plastic wrap and place in a ziptop freezer bag.