Beat the butter and powdered sugar with an electric mixer until combined.
Add the vanilla and keep beating until it's smooth and fluffy.
Add the flour and mix until incorporated.
Dump the dough onto a piece of plastic wrap and with your hands form a rectangular prism that is about 3 inches wide and 1 inch high. (Mine ended up being 9 x 3 x 1 in.)
Refrigerate for at least 2 hours.
Preheat the oven to 350°F
Remove from the fridge and slice the dough with a very sharp knife into ~1/4 inch slices. Place the cookies on an ungreased baking sheet.
Bake for about 12-14 minutes or until they just begin to brown on the edges. They start browning really quickly so if your oven tends to cook faster than recipes say, definitely check these earlier than the 12 minute mark.
Remove from the pan and cool on a wire rack.
Chocolate Coating:
Line 1 or 2 baking sheets with wax or parchment paper.
Melt the chocolate chips in a microwave. Start with 1 minute and then stir. Then heat in 15 second intervals, stirring in between until it is completely melted.
Dip a cooled cookie into the chocolate. I usually don't get much chocolate (if any at all) on the underside of the cookie because it makes weird shapes when you sit it down on the baking sheet. Scrape the excess chocolate off the backside of the cookies.
Then dip the cookie in sprinkles or sprinkle them over the chocolate (if you don't want to get chocolate in the rest of the sprinkles).
Place cookies on the baking sheet and put in the fridge for about 15 minutes or until the chocolate sets.
Store in an airtight container.
Yield about 30 - 35 cookies
Recipe by Birch Tree Baking at https://www.birchtreebaking.com/shortbread-cookies/