1/2 c. shortening
1/2 c. butter
1 tsp. vanilla
4 c. sifted confectioners' sugar (1 lb.)
2 tbsp. milk

Cream butter and shortening with mixer. Add vanilla. Gradually add sugar, one cup at a time, beating well on medium speed. Scrape sides and bottom of bowl often. When all sugar has been mixed in, icing will appear dry. Add milk and beat at high speed until light and fluffy. Keep icing covered with a damp cloth until you are ready to decorate.

For best results, keep icing bowl in refrigerator when not in use. Can be refrigerated in airtight container for 1 week. Re-whip before using.

To thin, use corn syrup rather than water or milk to prevent separating.