Heat oven to 350°F. Spray 13x9-inch pan with nonstick cooking spray. Prepare brownies as directed on package, using oil, 1/4 cup water and eggs. Spread batter evenly in sprayed pan.
Bake at 350°F. for 30 to 35 minutes. Cool 1 hour or until completely cooled.
Meanwhile, line cookie sheet with waxed paper. Melt margarine in small skillet. Stir in brown sugar and 1 teaspoon water. Cook over low heat for 6 to 8 minutes or until mixture is bubbly, stirring occasionally. Remove from heat. Stir in pecans. Spread evenly on waxed paper-lined cookie sheet. Cool completely.
In large bowl, combine whipping cream, milk and pudding mix; beat at low speed for 1 minute. Beat at medium speed for 1 minute or until fluffy. Spoon onto cooled brownie base; spread evenly. Cover; refrigerate at least 3 hours. Crumble pecan topping over each individual serving.