preheat oven to 375°F

grease 8x8 or 9x9 pan

in a medium bowl combine vegetable oil, egg, sugar, and milk, set aside

in a small bowl mix flour, baking powder and salt, then mix into wet ingredients, do not over stir.

pour cake batter into greased pan.

in a small separate bowl mix flour, brown sugar, cinnamon and softened butter. sprinkled topping onto cake batter, then lightly swirl into batter, do not mix.

then set in preheated oven and bake for 20 minutes, or until inserted toothpick is clean