1. Start by taking a large bowl and combining the all-purpose flour, salt, and sugar. Give it a good mix to make sure everything is evenly distributed.
2. Next, add in the cold, cubed butter. Using your fingers or a pastry cutter, mix it into the dry ingredients until you get a crumbly texture. It should look like sandy bits!
3. In a separate bowl, whisk together the egg, egg yolk, and vanilla extract until blended.
4. Pour the wet mixture into the dry ingredients and mix until a cohesive dough forms. This is where the magic happens!
5. Once your dough is ready, wrap it tightly in plastic wrap and pop it in the fridge for at least 30 minutes. This step is crucial for a flaky texture!
6. After refrigerating, roll out your dough and use it as a delicious base for your favorite cookies or tarts. The possibilities are endless!

Enjoy your baking adventure!