Heat oven to 350°F.

In medium bowl, mix all crust ingredients.

Press in ungreased 13 x 9-inch pan.

Bake 8 minutes; cool 10 minutes.

In medium bowl, stir all brownie ingredients until blended.

Carefully spread batter over cooled crust.

Bake 24 to 26 minutes or until toothpick inserted 2 inches from side of pan comes out clean or almost clean.

Cool completely, about 1 hour.

In medium bowl, beat powdered sugar, 2 tablespoons butter, the melted chocolate and vanilla with electric mixer on low speed until combined.

Beat in 1 tablespoon milk until blended.

Beat in additional milk, 1 tablespoon at a time, until frosting is desired spreading consistency.

Spread over cooled brownies.

Sprinkle with crushed pretzels.

Cut into 8 rows by 4 rows