For the torte:
1 (15-ounce) can sweet potatoes (may substitute 1 1/2 cups mashed)
4 ounces unsalted margarine or pareve butter substitute
6 large eggs, separated into whites and yolks
1/3 cup plus 2 tablespoons sugar
10 ounces semisweet chocolate, melted and cooled
Pinch salt
For the glaze:
2/3 cup strong coffee or cola (may substitute water)
1 1/4 cups semisweet chocolate, coarsely chopped, plus more as needed
For the matzoh buttercrunch praline:
4 to 6 sheets matzoh
1 cup unsalted margarine or pareve butter substitute
1 cup light brown sugar
3/4 cup semisweet chocolate or chocolate chips, coarsely chopped

For the torte: Preheat oven to 350 F.

Line bottom of a 9- or 10-inch springform cake pan with parchment paper.

Use a whisk or an electric mixer on low speed to blend the sweet potatoes and margarine or pareve butter substitute. Add the egg yolks, sugar and melted chocolate; mix well.

Place the egg whites in clean mixing bowl of a stand mixer or hand-held electric mixer. Add the salt; beat on medium speed just until whites become foamy. Gradually increase mixer speed to medium high, slowly adding the 2 tablespoons of sugar until stiff, glossy (but not dry) peaks form.

Fold one-third of beaten egg whites into chocolate mixture, then gently fold in remaining two-thirds of egg whites in 2 installments, blending well but taking care not to deflate mixture.

Transfer to prepared pan and bake for 35 to 45 minutes; cake will have risen and will look dry and slightly cracked on top when done. (Middle should be soft but firm.) Cool in pan for 20 minutes, then remove from pan and transfer to a wire rack (it can still be on the springform pan base, if desired).

For the glaze: Bring the coffee or cola to a gentle boil in a small saucepan over medium heat.

Add the chopped chocolate; reduce heat to medium-low and stir to melt chocolate and smooth into a glaze. If it seems too gloppy, add chopped chocolate as needed, stirring until a thick glaze forms. Let cool.

While cake is cooling, make the matzoh buttercrunch praline: Preheat oven to 375 F.

Stack 2 baking sheets on top of each other; line top one completely with aluminum foil, then place parchment paper on top of foil. (This is very important, as mixture becomes sticky during baking.) Fit the matzoh sheets in lined baking sheet, cutting or breaking extra pieces as needed to completely cover surface area.

Combine the margarine or pareve butter substitute and the brown sugar in a large, heavy-bottomed saucepan over medium heat; cook, stirring constantly, until mixture comes to a boil, then cook, stirring, for 3 minutes. Remove from heat, then pour or spoon the mixture over matzoh.

Transfer to oven; immediately reduce heat to 350 F. Bake for 15 minutes, checking every few minutes to make sure mixture is not burning. If it is browning too quickly, remove from oven and reduce heat to 325 F; return it to oven when temperature is at 325 to finish baking.

Remove from oven and sprinkle matzoh immediately with the chopped chocolate or chips. Let stand for 5 minutes so chocolate melts, then spread melted chocolate over the matzoh.

While still warm, cut into squares or odd shapes or shards. Refrigerate until set.

To assemble torte: Spread glaze over top and sides of cake. Use crushed pieces of matzoh buttercrunch praline to decorate sides, and arrange shards on top.

Makes 14 servings.