Zucchini Chocolate Chip Cake

This cake is very tasty. I veganized the recipe. This could use a little optimization yet. What I  need to do is figure out how to make it cakier and rise higher.

Ingredients:

1 cup packed brown sugar
1/2 cup granulated sugar
1/2 cup vegan butter
1/2 cup vegetable oil
2 flax eggs
1 tsp. vanilla
1/2 cup almond milk
2 1/2 cups all purpose flour
3/4 tsp. allspice
3/4 tsp. cinnamon
3/4 tsp. salt
2 tsp. baking soda
4 Tbsp. cocoa
2 1/2 cups grated/shredded zucchini
1 cup mini chocolate chips

Directions:

1. Preheat oven to 325 degrees. 
2. Grease and flour a 9x13 pan. 
3. Cream sugars, butter, and oil. 
4. Add eggs, buttermilk and vanilla. Stir to mix. 
5. Sift together dry ingredients. 
6. Mix all together except chocolate chips. 
7. After mixing well, gently fold in chips. Pour into pan. 
8. Bake for 45 minutes until toothpick comes out clean when inserted in center. 
9. Dust with powdered sugar or a fluffy light frosting.

Notes:

This may not need the flax eggs at all, given the zucchini acts as a moistener and slight binder. 1 tsp of vinegar may help the rising issue.