Zucchini brownies

These are probably the best brownies i have ever ate! I got the recipe from my co-worker Lisa, she brought in some recipe books and i copied this one:

1 cup butter, softened

1 1/2 cups sugar

2 eggs

1/2 cup plain yogurt

1 tsp. vanilla extract

2 1/2 cups all-purpose flour

1/4 cup baking cocoa

1 tsp. baking soda

1/2 tsp. salt

2 cups shredded zucchini

frosting:

2/3 cup semisweet chocolate chips

1/2 cup creamy peanut butter

In a large mixing bowl, cream butter and sugar. Add eggs, one at a time, beating well after each addition. Beat in yogurt and vanilla. Combine the flour, coca, baking soda and salt; gradually add to creamed mixture. Fold in zucchini. Pour into a greased 13x9x2 baking pan. Bake at 350 for 35 - 40 minutes or until a a tootpick insered near the center comes out clean.

Frosting: combine the choclate chips and peanut butter in a small saucepan. Cook and stir over low heat until smooth. Spread the frosting over the warn brownies. Yield: 1 1/2 dozen.