Cinnamon Zucchini Coffee Cake

Cinnamon Zucchini Coffee Cake
 1 1/3 c. brown sugar

1 1/3 c oil

1 egg 

1 c. buttermilk

1 1/2 t. vanilla

1 t. baking soda

1/4 t. salt

2 1/2 c. flour

1 1/2 c. grated zucchini

1 T. orange or lemon zest

For the Topping:

1 c. sugar

2 t. cinnamon

2 T. butter

2 T. butter

In a large mixing bowl, combine brown sugar and oil, beat well. Beat in the egg and vanilla.  Add the buttermilk, baking soda, vanilla, and salt. Gradually mix in the flour until just combined. Fold in zucchini and orange zest. Set aside.
Prepare the Topping: In a food processor combine: sugar, cinnamon, and butter, pulse until crumbly.

Pour half the batter into a greased 9x13 inch pan. Sprinkle half the cinnamon-sugar topping evenly over it. Add the remaining batter, then finish with the rest of the topping.
Bake at 325 for 45 minutes, or until the cake springs back when gently pressed and a toothpick inserted in the center comes out clean.  If making muffins bake for 20 to 25 minutes.