Cream butter; gradually add 1/4 cup sugar, beating until light and fluffy. Add egg yolks, one at a time, beating well after each addition.
Combine flour and soda; add to creamed mixture alternately with water, beginning and ending with flour mixture. Add vanilla; stir well.
Pat dough evenly in a greased 15- x 10- x 1-inch jellyroll pan. Spread orange marmalade evenly over dough in pan.
Beat egg whites (at room temperature) until frothy. Gradually add remaining sugar, 1 tablespoon at a time, beating until stiff peaks form. (Do not under-beat the mixture.) Spread meringue evenly over marmalade. Sprinkle pecans over top.
Bake at 350° for 25 minutes or until lightly browned. Cool. Cut into bars.