Ham Mousse In Sherry Aspic

• 3 gelatin (unflavored)
• 1 aspic
• 1 egg (white)
• 650 gr ham (cooked)
• 950 ml chicken broth
• 240 ml cream (heavy)
• 120 ml dry sherry
• 34 gr tomato paste
• 26 gr scallions
• 8 gr butter (unsalted)