Mix flour, baking powder and a pinch of salt together in a medium bowl and set aside.
In a large bowl, beat butter with a hand-held mixer (or stand mixer with paddle attachment), on medium speed for one minute or until smooth and creamy. Add sugars and mix on medium speed until light and fluffy. Mix in egg and vanilla. Scrape down sides and bottom of the bowl as required.
On low speed, slowly add dry ingredients and mix until combined. Add chocolate chips and sprinkles and mix for a few seconds until just combined. Cover dough and refrigerate for one hour or until mixture is firm.
Preheat oven to 160°c. Line two baking trays with baking paper.
Remove cookie dough from fridge. Use clean hands to roll 1 1/2 tablespoons of mixture into balls. Place balls on prepared tray at least 3cm apart.
Bake for 12 minutes or until lightly golden brown around the edges. Remove from oven and allow to cool completely on trays.
Melt chocolate in the microwave in 30 second intervals, stirring after each, until completely melted. Dip half a cookie in melted chocolate, then place back on tray and sprinkle chocolate half with extra sprinkles. Repeat with remaining cookies. Place cookies in the fridge for five minutes to set the chocolate, then store in an airtight container.
If you can’t find christmas 100s and 1000s, swap for rainbow ones or sprinkles of your choice