Preheat oven to 325 degrees.
Toast 1/3 cup poppy seed in pie pan for 15 minutes, stirring occasionally.
Remove from oven; cool.
Prepare cake mix accord- ing to package directions.
Fold in poppy seed; re- serve 1 tablespoon for icing.
Add 1/2 teaspoon va- nilla and 1 tablespoon lemon rind.
Bake in greased 10 x 5 x 3-inch pan for 1 hour or until cake tests done.
Cool for 20 minutes.
Cream butter in bowl; gradually beat in 1 cup sugar, remaining vanilla, milk and lemon juice.
Beat in remaining sugar gradually until light and fluffy.
Tint with food coloring as de- sired.
Spread on cake.
Sprinkle with lemon rind and poppy seed.
Refrigerate for 4 hours or overnight.