CHOCOLATE CHIP HAMANTASCHEN

Steps:

• Put the confectioners' sugar and the egg yolks in a food processor and blend. Add butter and lemon zest and process to blend. Gradually add the flour and the salt, pulsing until it forms a ball. Divide the dough in half, flatten each into a disk, wrap tightly in plastic wrap. Chill until firm, at least 1 hour or up to overnight.
• Meanwhile, prepare the filling: In a bowl, beat the egg yolks, sugar, cornstarch and cocoa powder until smooth.
• Pour the milk into a small saucepan with the vanilla bean. Over medium heat, bring to a simmer, then remove from heat and remove the vanilla bean. Scrape the inside of the bean and add to the pan.
• While whisking vigorously, pour 1/3 of the milk into the yolk mixture, then pour back into the saucepan. Continue to whisk constantly while simmering over low heat until the mixture bubbles and thickens into a creamy pudding consistency.
• Remove from heat, add the bittersweet chocolate and whisk until the chocolate has melted and the cream is smooth. Pour into a clean bowl and cover with plastic wrap, placed directly on the cream. Refrigerate until cool, at least 30 minutes. Fold in the chocolate chips.
• Preheat the oven to 350 degrees. Line 2 pastry sheets with parchment paper.
• Unwrap one of the chilled dough disks and place on a piece of parchment paper that has been dusted lightly with flour. Lightly dust the top of the dough with flour. Cover with a second piece of parchment paper. Let stand at room temperature until malleable, about 5 minutes. Use a rolling pin to press and roll out the dough into a 1/4-inch- thick round between the sheets of parchment, flipping the dough occasionally. Use a plain biscuit or cookie cutter or glass to cut 3-inch circles, placing the circles on the prepared baking sheet spaced 1 inch apart. Place the baking sheet in the refrigerator to chill until firm while you repeat the rolling/cutting process with the second round of dough.
• Remove the first pan of dough rounds from the refrigerator. Place a heaping teaspoon of the filling in the center of each, and press up the sides to form triangles, pinching the ends closed. Top the filled cookies with a few extra chocolate chips. If the dough is too firm, let stand a minute or two to soften; returning the baking sheet to the refrigerator if the dough becomes too soft. Repeat with the remaining dough rounds.
• Brush the tops with beaten egg. Bake until golden and dough is delicately firm all the way through, about 13-18 minutes, rotating the racks front to back and top to bottom after about 10 minutes.
• Place trays on wire racks for 10 minutes before transferring cookies on parchment to racks to cool completely.