1.  Cream shortening and sugar together.  Beat in the molasses, eggs, egg yolks and the flavorings, beating well.

2.  Combine the flour, baking soda and salt together, then add to creamed mixture alternately with the buttermilk.

3.  Divide the batter evenly between 2-10 x15 inch baking sheets and spread evenly.  Combine the crumb ingredients until crumbly.  Cover the one sheet with the biggest portion of the crumb mixture to make it easier to handle when putting the bars together.  Press the crumb mixture lightly into the batter on both sheets.

4.  Bake at 350 degrees for 15-18 minutes.  Cool completely.

5.  To prepare filling: Mix together the unbeaten egg whites, milk and vanilla.  Beat in the sugar.  Lastly beat in the shortening until filling is smooth.  Spread the filling evenly over the pan with the most crumbs on top.  (This can be a bit difficult, but there is no harm in getting crumbs with the filling as the filling is covered with the other pan of bars.)

6.  Flip the other pan over carefully.  (Don't attempt to remove the cookie sheet until the two layers are pressed lightly together, to encourage the bars to fall out of top pan.)  Cut bars into desired size and remove from bottom pan.  Store bars in the refrigerator.