Bring butter and eggs to room temperature. Grease and flour the bottom and sides of a 10-inch bundt or tube pan; set aside.

In large mixing bowl, beat butter with electric mixer until creamy. Gradually add the sugar, beating at medium speed until light and fluffy. Add eggs, one at a time, beating about 1 minute after each; scrape bowl frequently, guiding mixture toward beaters. Beat 2 minutes more.

Sift together flour, soda and salt. Add to creamed mixture alternately with sour cream, beginning and ending with flour mixture. Beat well after each addition. Add lemon, orange and vanilla extracts; beat just until thoroughly blended.

Pour batter into prepared 10-inch bundt or tube pan. Bake in preheated 350 degree oven for 1-1/2 hours, or until wooden pick inserted in center comes out clean and dry. Cool cake in pan on wire rack for 15 minutes; remove from pan. Cool completely. Sprinkle with confectioners' sugar, if desired.