In a mixing bowl, cream the butter and 50 g of sugar together until light and fluffy.
Add the flour gradually, mixing until a soft dough forms. Stir in vanilla extract and salt if using.
Roll the dough into small balls and gently flatten them, or shape them with a cookie cutter.
Place the cookies on a parchment-lined baking sheet and sprinkle with the remaining 50 g of sugar.
Preheat the oven to 350°F (175°C) and bake for 12-15 minutes, or until the edges are lightly golden.
Allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack.
Serve and enjoy with tea, coffee, or as a sweet snack.