Line 3 large baking trays with baking paper. Set aside.

Sift together flour and salt into a medium bowl. Set aside.

Place butter and sugar in a large bowl. Using an electric hand held mixer or stand mixer, cream butter and sugar until light and fluffy on medium speed, about 4-5 minutes.

Add egg and vanilla extract. Beat until just combined.

Reduce speed to low and slowly add half of flour mixture. Beat until just combined.

Add remaining flour mixture. Scrape down the bowl. Beat again on medium speed until combined, about 30 seconds.

Add milk and beat again until just combined. Add more milk if needed to achieve the right piping consistency.

Transfer batter to a large piping bag fitted with star tip (I used 1M tip).

Pipe cookies onto the baking tray 1 and ½ to 2 inches apart.

Refrigerate for 30 minutes.

Preheat oven to 180C or 350F.

Bake cookies, in batches, until bottom edges are slightly browned, about 12-15 minutes.

Cool on the baking tray for 10 minutes before transferring to a wire rack to cool completely.

Dip the cookies in melted milk chocolate. Decorate with sprinkles.

Store plain butter cookies in an airtight container for a week. Chocolate covered cookies can be stored in an airtight container for about 3 days.