In large mixing bowl combine butter, peanut butter, sugar, brown sugar, eggs, and vanilla extract. Beat until well blended. Stir together flour, soda, and salt. Add about 1/3 of the flour mixture to egg mixture. Stir until blended. Add half of the zucchini. Stir until combined. Repeat, adding 1/3 of flour, then zucchini, ending by stirring in the last of the flour. Stir in milk chocolate.
Spoon batter into prepared pan. Spread evenly. Bake for 55 to 65 minutes or until tooth pick inserted in center comes out clean. Cool 10 minutes. Remove from pan. Cool.
To prepare glaze, combine powder sugar, butter, and 2 tablespoons hot water. Mix well. Stir in peanut butter and vanilla. Add enough of remaining water to make desired spreading consistency. Spread over top of cake allowing glaze to run down sides.
To serve cut into wedges. Makes 16 to 20 servings.
Why this recipe represents holiday and tradition:
I created this recipe over 30 years ago. Originally I made it as a bar, but now changed it to be a bundt cake. The recipe has been handed down to my children and now this is one of my granddaughter's favorite cakes. Each year when Zucchini are plentiful my daughter asks if she can have a few zucchini just to make this recipe.