Step 1

In the bowl of a stand mixer with the paddle attachment, cream the butter and powdered sugar on medium speed until light and creamy.Pro tip - do not cream too long, just until the sugar is melted, as we do not want to add too much air into our dough.

Step 2

Add the egg and egg yolk one at a time. Followed by the vanilla extract.

Step 3

Next, add the flour, salt, and cornstarch. Combine well into a soft dough. Pro tip - you can combine the dry ingredients first, then add them to the dough.

Step 4

Divide the dough into two discs. Wrap well in plastic wrap and chill for at least 2 hours or until firm enough to roll.Pro tip - it is important to chill until the dough is firm enough to roll. Otherwise, it will be difficult to shape the cookies.

Step 5

Place the pistachio nuts in a food processor and pulse to a coarse powder. Set aside

Step 6

Crumble the halva in a bowl until it resembles almost bread crumb consistency.

Step 7

Then, in a medium bowl combine the halva and pistachio together. Set aside until ready to fill.

Step 8

Roll the chilled cookie dough on a lightly floured surface to about 1/8 thickness.Pro tip - You want the cookies thin enough so you can overlap the edges without cracking but thick enough so they won't become too hard.

Step 9

Using a 3-inch or 3 1/2 inch cookie cutter, cut as many discs as you can and place them on a baking tray. Pro tip- Line the baking tray with parchment paper or a silicone mat for easy clean-up.

Step 10

Add about a tablespoon of filling in the center. Pro tip -Do not add too much filling because the hot filling will force the cookies to open during baking.

Step 11

Dampen the disc edges very lightly with water or egg whitePro tip - you need just a dap of the water or egg whites otherwise it will be difficult to secure these folds

Step 12

Overlap the three corners as shown in the video. Fold the first two sides over at one end. Then overlap the third side under the first and under the second.Pro tip -At all times each side should be one under and one over the other. Sounds complicated but if you see the video it's pretty simple.

Step 13

Once all cookies are filled - chill them in the fridge while you preheat the oven.

Step 14

Preheat the oven at 375 °F / 190 °C / Gas Mark 5

Step 15

Brush the cookies with egg wash. Bake for 10 to 12 minutes until the edges are lightly golden.

Step 16

Cool on the baking tray for 5 minutes transfer to a wire rack to cool completely before you store them in a cookie jar. These will stay for up to a week.