Add egg yolk and vanilla extract. Mix until everything is well-blended.
Add sour cream and mix again. I think sour cream added some moisture to these cookies and prevented them from becoming very hard.
Add flour, baking powder and salt.
Mix everything. The batter will start to curdle and look odd. That’s perfectly normal… you haven’t done anything wrong.
When the curdling happens, it’s time to use your hands to start mixing until you form a ball of cookie dough!
Roll this dough between 2 sheets of wax paper or parchment paper.
Use a cookie cutter to cut out cookie shapes.
Bake these cookies on a cookie tray, lined with parchment paper at 350 degrees for 6 minutes. Then rotate your tray and bake for another 3 minutes. Your baking times may vary depending on the thickness of your cookies. Cookies are done when they are light golden brown along the edges.
Allow the cookies to cool down completely before removing them from the parchment paper. Enjoy!
Video
Notes
You are only using an egg yolk... NOT the whole egg!
To make Orange sugar cookies, replace vanilla extract with ½ tbsp orange extract or orange oil and also add ½ tbsp orange zest. You can add more or less zest depending on your preference.
To make Almond sugar cookies, add ¼ tsp vanilla extract and ½ tsp almond extract.
To make Spiced sugar cookies, add ½ tsp cinnamon powder and ¼ tsp nutmeg powder.