This is an old family recipe with some modifications--I doubled the eggs, used 1/4 cup honey instead of the original 1/3 cup sugar, and added pumpkin pie-type spices. I think I actually prefer it without the spices, or with just the cinnamon, but it's good both ways. I use whipped cream instead of the traditional marshmallow topping, or it's good with no topping at all.
It turns out quite fluffy.
4 large sweet potatoes (the darker, sweet deep orange kind often called yams or garnet yams in U.S. markets), cooked and mashed (drain water if boiled)
1/4 cup butter
1/4 cup honey
4 eggs, thoroughly beaten
1 tsp salt (I put in slightly less)
2 tsp. baking powder
1 tsp cinnamon (optional)
Scant 1/2 tsp ginger (optional)
1/4 tsp nutmeg (optional)
1/2 tsp. vanilla extract or maple syrup(optional)
Butter large baking dish (I used 9" x 13" x 2")
If mashed sweet potatoes are still warm, stir butter in and allow to melt. Add honey, and eggs and mix well. Add dry ingredients (either mix together or add baking powder last), beat until well-blended, and pour into baking dish. Dot with butter if desired.
Bake at 350 degrees F for 35-40 minutes. Serve warm or cold, topped with whipped cream if desired.