Neapolitan Brownies

To prepare brownies, bake brownies according to package instructions; cool completely in pan on a wire rack. Cut brownies into squares; remove from pan.
To prepare vanilla icing, place powdered sugar, meringue powder, and vanilla in bowl of a heavy-duty stand mixer. With mixer running on medium speed, gradually add 7 tablespoons of the water. Beat until well combined, about 3 minutes, stopping to scrape sides as necessary. If necessary, add up to 1 more tablespoon water, and beat until desired consistency is reached. Set aside.
To prepare strawberry icing, place powdered sugar, jam, meringue powder, and vanilla in bowl of a heavy-duty stand mixer. With mixer running on medium speed, gradually add 6 tablespoons of the water. Beat until well combined, about 3 minutes, stopping to scrape sides as necessary. If necessary, add up to 1 more tablespoon water, and beat until desired consistency is reached.
To assemble, place an offset spatula in hot water for 3 to 5 seconds. Dip right edge of 1 brownie square (about 1/3 of brownie) into vanilla icing, and smooth edges using warm offset spatula; wipe spatula clean. Dip left edge of the brownie square (about 1/3 of brownie) into strawberry frosting and smooth edges with offset spatula; wipe spatula clean. Transfer brownie to a wire wrack. Repeat procedure with remaining brownie squares. Let sit at room temperature until icing is set, about 30 minutes.