In a bowl, stir together 1/2 cup applesauce and gelatin. Let sit 10 minutes.
Meanwhile, combine 3/4 cup applesauce with sugar and boil for 7 minutes. Add the cold mixture into the hot pan, and boil for 7 more minutes, stirring constantly.
Remove from heat, and stir in vanilla and nuts (if using). Pour into greased loaf pan, and refrigerate. When cold and solid, cut into small pieces. Store in refrigerator.
To avoid pork/beef, use Kosher gelatin. To avoid fish and all meat, use vegan gelatin.