8 ounces unsweetened chocolate
8 ounces (2 sticks) unsalted butter plus more for buttering pan
8 ounces (2 generous cups) walnuts
5 large eggs
2 teaspoons vanilla extract
1/2 teaspoon almond extract
1/4 teaspoon salt
1 teaspoon powdered instant espresso*
3 3/4 cusp granulated sugar
1 2/3 cups sifted unbleached flour
2 (14- or 15.4-ounce) bags York chocolate-covered
peppermint patties, unwrapped
* Medaglia D'Oro brand from an Italian grocery store is good.
Adjust an oven rack one-third up from the bottom and preheat oven to 425 degrees F. Line a 13 x 9-inch pan as follows: Invert the pan and center a 17-inch length of aluminum foil, shiny side down, over the pan. With your hands, press down on the sides and corners of the foil to shape it to the pan. Remove the foil. Turn the pan right side up. Place the foil in the pan, and very carefully press it into place in the pan.
Place a piece of butter (additional to the 8 ounces in the ingredients list) in the pan and put the pan in the oven. When the butter is melted, use a pastry brush or a piece of crumpled plastic wrap to spread the butter all over the foil. Set the prepared pan aside.
Place the chocolate and 8 ounces butter in the top of a large double boiler over hot water on medium heat, or in a 4- to 6-cup heavy saucepan over low heat. Stir occasionally until the chocolate and butter are melted. Stir to mix. Remove from the heat and set aside.
Break the walnuts into large pieces; set aside.
In the large bowl of an electric mixer, beat the eggs with the vanilla and almond extracts, salt, espresso, and sugar at high speed for 10 minutes. On low speed add the chocolate mixture (which may still be warm) and beat only until mixed. Then add the flour and again beat on low speed only until mixed. Stir the nuts in by hand.
Pour half the mixture (about 3 1/2 cups) into the prepared pan and smooth the top. Place a layer of the mints, touching each other and the edges of the pan, all over the chocolate layer. Cut some mints to fill in large spaces on the edges. (You will not use all the mints. There will be some left over.) Pour the remaining chocolate mixture all over the pan and smooth the top. Bake for 35 minutes, reversing the pan front to back once during baking to ensure even baking. At the end of 35 minutes, the cake will have a firm crust on top, but if you insert a wooden pick in the center, it will come out wet and covered with chocolate. Nevertheless, it is done. Do not bake any longer.
Remove the pan from the oven; let stand until cool. Cover the pan with a cookie sheet and invert the pan and the sheet. Remove the pan and the foil lining. Cover the cake with a length of wax paper and another cookie sheet and invert again leaving the cake right side up. Now the cake must be refrigerated for a few hours or overnight before it is cut into bars.
When you are ready to cut the cake, use a long, heavy knife with a sharp blade either serrated or straight-try both. Cut the cake into quarters. Cut each quarter in half, cutting through the long sides. Finally, cut each piece into 4 bars, cutting through the long sides. (These are better in narrow bar shapes than in squares.)
Pack in an airtight box or wrap individually in clear cellophane, wax paper or foil. These freeze perfectly and can be served very cold or at room temperature. Makes 32 jumbo brownies.