• Preheat the oven to 180 C (350 F) and line a cookie sheet with parchment paper.In a bowl, cream together the butter, sugar, vanilla and salt.
•  Mix in the flour to form a dough. The dough should be firm and thick.

For the thumbprint cookies:

• Roll the dough into 1 tbsp sized balls. Place on the cookie sheet and press each one down slightly with your thumb to produce an indentation. The sides of the cookie balls may crack when you do this- you can either smooth out the cracks with your fingers, but I find that they don't crack as much if you press them down as soon as you've rolled the ball. 
• Fill each indentation with 1/2-1 tsp raspberry jam or any jam of your preference. Bake for 15-17 min. Cool completely before glazing.
• For the glaze, mix 1/2 cup icing sugar with a 1-2 tbsp of water till pipeable but still loose. Using a ziplock bag with a corner snipped off, drizzle the cookies with glaze. You could also just skip the glaze and dust with icing sugar- or keep them plain.

For the snowball cookies:

• Add 1 cup of finely chopped walnuts or pecans to the cookie dough recipe. Roll the dough into 1 tbsp sized balls using your hands, and place on the cookie sheet. Do not press the mounds of dough down. 
• Bake for 15 min (they will puff up slightly as they bake). If you have to, it is better to under-bake than over-bake the snowballs. While still warm, roll the cookies in the confectioners' sugar. The coating will immediately start to melt- this is what you want.
• Place the cookies back onto the tray and let them cool completely.Once the cookies have cooled completely, roll them once more in the confectioners' sugar- this is when they really start to look like snowballs.

For the hazelnut and chocolate slice n'bake:

• Add 1 cup of chopped hazelnuts to the cookie dough recipe. Divide the dough into two portions and place each one onto a sheet of cling wrap. Form each portion into a log shape about 1.5 inches (3-4 cm) height-wise. 
• Cover each log completely in the cling wrap and chill the logs for at least an hour in the refrigerator or until firm. Chilling is necessary in order to slice the cookies properly.
• Slice the log to form circles .5 inches (1 cm) thick and 1.5 inches (3-4 cm) wide. Place the circles onto the cookie sheet slightly apart, and bake for 15-17 minutes.
• In the meantime, melt 200 g chocolate (I use half milk and half dark) in the microwave stirring every 20 seconds or over a double boiler. Stir in the 2 tsp of vegetable oil. This ensures that the chocolate stays glossy.
• Dip the cookies into the chocolate about halfway, then place back onto the cookie sheet to set. Chill the tray so to harden the chocolate faster.