Pistachio Marzipan Brownie Tart

Crust:

• Combine flour, cocoa, baking powder, salt and sugar in a food processor and pulse to combine. Add the butter and pulse until it resembles breadcrumbs.
• Add the beaten egg and run the food processor until the dough comes together.
• Divide the dough into ⅓ and ⅔ portions. Shape in discs, wrap separately in plastic and refrigerate. Chill for one hour. It can be made the day before, but will need to warm up before rolling to prevent it from breaking up.

Filling:

• First blanch the pistachios by bringing a large pot of water to a boil and adding the shelled pistachios. Boil for 30-60 seconds. Test doneness by placing 1 pistachio under cold running water and seeing if the reddish skin comes off easily. Once it does, drain and rinse all the pistachios with cold water.
• One by one, squeeze the pistachios to remove their skin. Doing this will keep the marzipan bright green. Once they are all skinned, place them on a towel-lined baking tray and allow to dry for at least 3 hours. Do not dry in the oven, as the color may fade.
• Combine pistachios and sugar in a food processor and grind as finely as desired. Add egg whites and process until well blended. (If you didn't blanch the pistachios and the marzipan is a little brown, you can add a drop or two of green food coloring.) If you are making the marzipan in advance, scrape into a container and refrigerate for up to a week or freeze for up to 6 months. If you plan to use the marzipan the same day you make the tart no refrigeration is necessary.

Put it together:

• Preheat oven to 350 F and grease a 9" tart pan or cake pan with removeable sides.
• Mix the pistachio marzipan with approximately ½-¾ of a beaten egg to make a fairly soft, spreadable filling. Set aside.
• Roll out the larger portion of dough between 2 pieces of plastic wrap until it is about 1" larger than your pan on all sides (10 inch diameter). Make sure there are no creases in the plastic wrap. Use this piece of dough to line the pan, pressing it to the sides of the pan so it doesn't fall inward.
• Spread the pistachio marzipan evenly over the dough and fold in the dough edges so they rest on it.
• Reuse the plastic wrap to roll the smaller piece of dough into an 8½" circle. It should be slightly smaller than the cake pan. Trim it so the edges are neat. Moisten the edges of the dough in the pan and lay the smaller circle on top. Press the edges gently together to seal. Brush with the leftover beaten egg and prick with a fork in several places.
• Bake for 30-35 minutes. Remove from the oven and allow it to cool at room temperature until the pan is cool enough to touch. Approximately 30 min. Leave to cool in the pan, then transfer carefully to a serving plate. If you can stand it, wrap this and let it sit for a day or two before serving for best flavor.

• Finely grind 1 cup pistachios and 1/4 cup sugar in processor. Bring milk and ground pistachio mixture to boil in heavy large saucepan. Remove from heat. Mix in almond extract.
• Whisk egg yolks and remaining 1/2 cup sugar in medium bowl. Gradually whisk in hot milk mixture. Return custard to saucepan. Cook over low heat until custard thickens and leaves path on back of spoon when finger is drawn across, stirring constantly, about 10 minutes (do not boil). Strain into large bowl. Chill until cold, about 2 hours.
• Stir 1 cup whipping cream and chopped pistachios into custard. Process mixture in ice cream maker according to manufacturer’s instructions.