Shake all ingredients except for the bitters in a shaker, without ice. Hold on tight, as the egg will foam and expand the air in the shaker. Carefully remove the shaker lid. Add ice cubes and shake again until well chilled. Hold on tight. Strain into 2 coupes. Spoon out the ice from the shaker and then spoon any remaining foam atop the 2 drinks. Gently spray a mist of Angostura bitters onto each drink. Alternately, decoratively add several drops of bitters on the foam.