Preheat oven to 350. Grease 8x8 square pan with cooking spray.
Streudel:
In a small bowl, combine all of streusel ingredients and set aside.
Cake:
In a large bowl stir together pumpkin oil, sour cream and eggs. Add in all of dry ingredients and stir altogether. Pour half of the batter into baking pan; sprinkle batter with half the streudel. Pour the rest of batter in pan. Top with struesel.
Bake 35-40 minutes until toothpick inserted comes out clean.
While cooling, make frosting: in a small bowl stir together powdered sugar and syrup. Drizzle frosting over warm cake. Enjoy