Toasted Pistachio & Chocolate Torta

12 ounces whole pistachios, shelled
1 1/4 cups sugar, divided
8 ounces bittersweet chocolate, coarsely chopped (I used chocolate chips)
8 ounces unsalted butter
6 large eggs, separated, at room temperature
2 tablespoons Frangelico
Cocoa powder, for sprinkling
To remove the skins from the pistachios, bring a medium sized saucepan filled halfway with water to a boil. Meanwhile, fill a medium sized bowl with ice water and keep near by. Once the water comes to a rapid boil, quickly add the shelled pistachios and boil for about 30 seconds.  Quickly remove the pistachios from the boiling water using a slotted spoon and place them in the bowl of iced water.  Allow them to sit for a few minutes, then again using the slotted spoon, transfer the pistachios to a clean dish towel that is laid flat on the counter.  Using the palm of your hand, continually roll over the pistachios. Do this action several times and the skin will easily slide off (well, most of the time. Some you will have to peel off).  Place the de-skinned pistachios in a colander and give them a quick rinse to remove any small remaining pieces of skin. Shake off excess water. 
Transfer pistachios to a cookie sheet lined with aluminum foil. Be sure they're placed in an even layer and not too over crowed. I used two sheets since they didn't all fit on one. Roast the pistachios for about 10 minutes, stirring halfway through until they've slightly darkened in color. You should be able to smell their nutty aroma and you'll know they're done.
Meanwhile, maintain oven temperature at 325 degrees Fahrenheit. Grease a 9" round pan with a removable bottom as set aside.
Allow the pistachios cool for about 5 minutes. Grind the nuts in a food processor in three batches, pulsing each batch with 2 tablespoons of sugar, using 6 tablespoons in all.
Place the chocolate and butter in a heat safe bowl over simmering water and melt together (or in micowave). Set aside.
Beat the egg yolks in a large bowl with an electric mixer until lemon-colored, about 5 minutes. Gradually beat in 10 tablespoons of the sugar.  Add the chocolate mixture, stirring to mix well.  Add the ground pistachios and stir to incorporate. Add the 2 tablespoons of Frangelico and stir to combine. 
In a clean metal bowl, beat the egg whites with the remaining 1/4 cup sugar until they form firm peaks.  In two additions, fold the egg whites into the chocolate mixture.  Pour the batter into the prepared cake pan and smooth the top. Put the pan on a cookie sheet and bake for 1 1/2 hours or until a toothpick inserted in the center comes out clean.  Let cool in the pan on a wire rack for 15 minutes before removing the sides of the spring form pan, then cool completely.
Dust with cocoa powder and slice.
recipe adapted from Alexandra's Kitchen