Caviar Mousse

Sprinkle gelatin over water and let stand until softened, in a small sauce pan, then heat over low heat, and stir constantly until gelatin melts, 1 to 2 minutes. Remove from heat and add sour cream, mayonnaise, lemon juice, onion, & sugar , blending well. Place caviar in strainer and rinse carefully with cold water. Shake strainer to remove excess water. Reserve 1 tablespoon caviar. Add remaining caviar to sour cream mixture, stirring gently. Season to taste with salt and white pepper. Turn into greased 2-cup mold or into 8 to 10 small individual molds and chill until firm, about 3 to 4 hours. Unmold on serving plate. Place about 6 tablespoons sour cream on top of large mold or 1 tablespoon on each individual mold. Place some of reserved caviar &chopped green onions on top of sour cream. Surround with parsley and accompany with toast rounds and cucumber slices.