Also, you should be aware that this takes a long, long time to make. I made it the day before...good thing, too, because I wouldn't have had time to make it the day of the meal along with all the other food.
And one more thing: there is nothing about this that is specifically Passover. Make it anytime!
2. In a 375F oven, bake the carrots and sweet potatoes with the chicken fat (or margarine), brown sugar, cider, salt and pepper to taste, lemon juice and cinnamon until the vegetables are soft (about 1 hour). Puree the mixture.
3. Dice the onions and sweat them slowly in a covered heavy pan with 3 T. peanut oil*, cooking slowly until the onions are translucent (about 20 minutes), stirring occasionally. Puree and adjest the consistency by adding about a cup of water until the mixture has reached the texture of whipped cream.
4. When the carrot-and-sweet-potato mixture is cool, add 3 eggs and 1 cup of the onion puree. Set aside.
5. Boil the Maine potatoes and mash until smooth, loosening with the remaining onion mixture. Add salt and pepepr to taste. When cool, add the remaining 3 eggs and fold in well.
6. Heat the prunes in about 1 inch of water for about 5 minutes, drain and puree.
7. Cook the asparagus in boiling water for about 2 minutes and then plunge into ice water. Dry.
8. For each terrine---this recipe makes two---grease a loaf pan. Lay the dry leeks across the pan to line it, alternating tops and bottoms from one side to the other so that the ends overlap the top by about 2 inches.
9. Put in 1/4 of the sweet potato/carrot mixture. Bury 3 to 5 asparagus spears in the sweet potato-carrot mixture. Atop the layer of sweet potato mixture, spread a thin layer of prunes.** Atop that, put half the white potato mixture. Cover with 1/4 of the sweet potato/carrot mixture, again pushing in 3 to 5 asparagus spears. Repeat for the second terrine.
10. Seal the terrine by folding the leeks over the top. Cover with foil and bake in a bain-marie (hot water bath) 1 hour at 375F.
11. Cool completely in the bain-marie outside the oven. Weight down with heavy cans or a brick and place in refrigerator for 1 day. Slice while chilled with a very sharp slicing knife, making sure to wipe knife after each slice and warm slightly in the oven before serving.