Step 1: Cream Butter, Sugar, and Vanilla

Into a mixing bowl, add 3/4 cup of caster sugar, 200 grams of room temperature butter, and 1 teaspoon of vanilla extract. Using an electric mixer, beat these ingredients together until the mixture is nice and creamy.

Step 2: Incorporate the Egg

Add 1 egg to the creamy mixture. Beat it in with the electric mixer until the mixture is smooth and well combined.

Step 3: Add Flour and Sprinkles

Sift in 2 cups of plain flour and add 1/2 cup of hundreds and thousands (rainbow sprinkles). Using a wooden spoon, gently mix everything together until all ingredients are combined and form a slightly crumbly dough.

Step 4: Shape the Dough Log

Turn the dough out onto a lightly floured surface. Shape the dough into a 30 cm (approximately 12 inches) long log, ensuring it is relatively even all the way through.

Step 5: Chill the Dough

Wrap the dough log tightly in plastic cling wrap, making sure it's completely covered. Place it in the fridge for about an hour or two to allow it to firm up.

Step 6: Slice the Cookies

Once the cookie dough has firmed up nicely, unwrap it. Using a knife, slice the log into 1 cm (approximately 0.5 inch) thick pieces.

Step 7: Bake the Cookies

Arrange the sliced cookie pieces on a baking tray lined with non-stick baking paper, leaving some space between them. Place the tray into a preheated oven at 180°C (350°F) and bake for about 10 to 12 minutes, or until they are nice and golden. Ensure to bake one tray at a time for even cooking.

Step 8: Cool and Serve

Once baked, remove the cookies from the oven. Leave them on the baking tray for about 5 minutes to firm up. After 5 minutes, transfer them onto a wire rack to cool completely before serving.

• Ensure butter is at room temperature for easier beating.

• Bake one tray of cookies at a time for best results.

• Allow cookies to firm up on the tray before transferring to a wire rack.

• Experiment with different colored sprinkles or chocolate chips.

• Add citrus zest (lemon, orange) for a different flavor profile.

• Dip cooled cookies in melted white chocolate and add more sprinkles for extra decadence.