Easy Christmas shortbread cookies

Mix the flour with the sifted baking powder and set aside.
In a bowl, pour the sugar, cold butter pieces, vanilla extract and egg.
Mash the butter with the tines of a fork then mix everything together.

Add the flour mixture and mix first with a fork then with your hands.
Pour the mix onto the work surface.
Quickly knead the dough with your hands until it forms a smooth, homogeneous dough ball.
If the dough sticks to your hands, add a tiny bit of flour, without overdoing it.

Close the dough in plastic wrap, crush a little with your hands and place in the refrigerator for an hour.

Once the resting time has passed, place the dough between two sheets of floured parchment paper.
Roll out the dough with a rolling pin to a thickness of about 3-4 millimeters.

Using the 4-5 cm scalloped round cookie cutter, form the cookies and arrange them slightly apart on the cookie sheet.
The scraps of can be kneaded again to form more cookies.

Bake the Cookies in a preheated oven, in static mode, at 190°C for about 15-20 minutes. The cookies will be ready when they begin to take color in the edges.

Transfer the cookies to a wire rack and let them cool completely.

Whisk the egg whites with the lemon juice. When they begin to foam, add the sifted powdered sugar a little at a time. Try not to form lumps.
Once all the sugar has been combined, stir with a spatula to remove bubbles to make a smooth, velvety mixture.