Grease bundtpan. Cut out a piece of waxed paper to fit in bottom; grease waxed paper.
Beat butter and sugar together until thouroughly mixed. This should take bout 7 minutes. Beat in egg yolks.
Sift together flour, salt and baking soda; sift 3 more times.
Beat in flour mixtue slternately with sour cream starting and ending with flour Beat in extract.
In a separate bowl, beat egg whites until stiff. beat in half of the egg whites into the cake batter. Fold in remianing egg whites. Spoon into prpared pan.
Bake at 300 for 1 3/4 to 2 hours or until it tests done. Cool for 10 minutes; remove from cake pan, cool completely.
Make a glaze with powdered sugar, almond extract and milk. Sprinkle with slivered almonds.