This rich, dense flourless chocolate cake has a firm consistency, so it can be sold in slices, if desired. Suggest that your customers serve it with sweetened whipped cream or premium vanilla ice cream.

Preheat the oven to 350°F. Spray or grease a 9-inch springform pan and line the bottom with waxed paper or parchment paper.

In a microwave-proof bowl, heat the chocolate with the coffee in the microwave on high for about 2 minutes, stirring occasionally, until melted and smooth. Or melt in the top of a double boiler over hot water. Let cool.

While the chocolate is cooling, in a large bowl, with an electric mixer, beat the egg whites until soft peaks form. Sprinkle 6 tablespoons of the sugar over the egg whites and beat to incorporate, then continue beating until the egg whites form stiff, glossy peaks. Set aside.

In another large bowl, using the electric mixer, beat the yolks with the remaining 2/3 cup sugar until thick and light, about minutes. Beat in the cooled chocolate and the salt. With a rubber spatula, gently fold in the egg whites. Fold in the nuts. Pour the batter into the prepared pan.

Bake the cake in the center of the oven for 30 minutes, or until a cake tester or toothpick inserted into the center comes out clean. Cool the cake completely on a wire rack before removing the pan sides. The cake may fall slightly in the center as it cools, and it will be only about 1 1/2 to 2 inches high.

Bake Sale Tip: Sell the cake whole or cut it into slices. Place them on colorful paper plates, wrap in colored cellophane, and tie with a ribbon in a contrasting color. Or use small aluminum takeout containers with clear plastic lids, and tie the containers with colorful ribbons. You can find the containers at some party supply stores or online from restaurant supply companies. Or ask a local restaurant if they'll sell you some.