Zucchini Brownies

1/2 C canola oil
1 1/2 C sugar
2 tsp vanilla
2 C all-purpose flour
1/2 C unsweetened cocoa powder
1 1/2 tsp baking soda
1 tsp salt
2 C shredded zucchini (I use the small-sized grater)
1/2 C chopped walnuts (optional)

Frosting:
6 T unsweetened cocoa powder
1/4 C salted butter
2 C powdered sugar
1/4 C milk
1/2 tsp vanilla

Brownies:
Preheat oven to 350 degrees. Grease and flour a 9x13-inch baking pan. Mix oil, sugar, and vanilla together in a large bowl until well blended. Combine flour, cocoa, baking soda, and salt in a separate bowl. Stir into sugar mixture until thoroughly combined. Fold in zucchini and walnuts. (Batter will appear dry at first but will become more wet as you mix.) Spread evenly into prepared pan and bake 25 to 30 minutes or until brownies spring back when gently touched. Cool completely before frosting.

Frosting:
Melt cocoa and butter in a small pan; set aside to cool. Blend powdered sugar, milk, and vanilla in a medium bowl. Stir in cocoa mixture. Spread over cooled brownies before serving.