Combine brown sugar, cinnamon, and butter. Add peanuts. Set aside. Allow butter to come to room temperature. Cream butter, sugar and eggs. Add lemon rind. Combine flour, soda and salt. Add alternately with milk to butter-sugar mixture beginning and ending with flour. Pour half the batter into a greased 13 x 9 x 2 inch baking pan - spread batter with a spatula to cover pan. Sprinkle with half the topping. Add remaining batter and sprinkle with topping. Bake in a preheated 350 degrees F. oven for 30-40 minutes until golden and cake will spring back when pressed. Makes 14-16 servings.