Preheat oven to 350°F Grease a 9x13-inch baking pan.
Microwave sugar, butter and water in large microwave-safe bowl on high power for 4-5 minutes or until mixture bubbles, stirring once. Remove from heat. Add chocolate baking squares; stir until melted.
Stir in eggs one at a time until incorporated. Stir in vanilla. Add flour, baking soda and salt; stir well. Stir in nuts. Pour into prepared baking pan.
Bake for 15-20 minutes or untill wooden pick inserted in center comes out slightly sticky. Remove to wire rack to cool completely.
FOR THE SAUCEPAN METHOD: Heat sugar, butter and water in medium saucepan just to boiling, stirring constantly. Remove from heat. Add chocolate baking squares; stir until melted. Proceed as above.
CREAM CHEESE BROWNIE VARIATION; Prepare brownie batter; do not pour in pan. Beat 8oz. softened cream cheese, 1/2 cup granulated sugar, and 1 teaspoons vanilla in small mixer bowl until smooth. Beat in 1 egg. pour brownie batter into pan. Spoon cream cheese mixture over top; swirl with spoon. Bake for 20-25 minutes.
PEANUT BUTTER BROWNIE BROWNIE VARIATION: Prepare brownie batter without nuts; do not pour into pan; combine 1/2 cup peanut butter, 3 tablespoons granulated sugar and 2 tablespoons milk in microwave-safe bowl. Microwave on high for 45 seconds; stir until smooth. Pour brownie batter into pan. Spoon peanut butter mixture over top; swirl with spoon. Bake 20-25 minutes.
ROCKY ROAD BROWNIE VERSION: Prepare brownie batter without nuts; Bake as directed. While still hot, sprinkle the 1/2 cup miniature marshmallows, 1/3 cup chopped nuts, and 3/4 cup semi-sweet chocolate chips. Bake for another 2-3 minutes or until marshmallows are puffed and chocolate chips are shiny.