In a mixing bowl, beat the eggs, sugar and vanilla until thick and lemon-colored, about 4 minutes. Combine the flour, baking powder and salt; add to egg mixture. Beat on low speed just until combined.
Add the milk and butter; mix well. Pour into a greased 13-in. x 9-in. x 2-in. baking pan. Bake at 350 degrees F for 30-35 minutes or until a toothpick inserted near the center comes out clean. Cool on a wire rack. Cut into squares. Cover and freeze overnight.
For frosting, in a mixing bowl, combine confectioners' sugar, milk, vanilla and salt; beat until smooth. frosting the top and sides of frozen cake squares; roll in peanuts. Place on wire racks to dry.
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