Melt 2 cups of the white chocolate chips, set aside 1/2 cup. Mix the sprinkles into the remaining 1 1/2 cup. Pour into a silicone candy mold, let excess drip off. Using an offset spatula or bench scraper, scrape off excess chocolate. Place in the fridge for 5 minutes to harden.
While chocolate mold is setting up, make the ganache. Place the butter, remaining 1 cup of chocolate chips, and the condensed milk into a medium-sized microwave-safe bowl.
Microwave on high one minute. Let stand one minute. Stir until smooth and combined, this may take a few minutes. Pour into a pastry*** bag and cut off a very small amount off the tip. Fill molds almost all the way to the top with the ganache, making sure there is a small space to be able to add more melted chocolate. Place in the fridge 10 minutes to set.
Once set, pour the remaining melted white chocolate from step 1 on top. Using an offset spatula or bench scraper, scrape off the excess chocolate. Place in the fridge 5 minutes to set. Pop chocolates out of the mold, enjoy!
Notes
*For the small silicone mold I used, I could make 36 truffles. **Use flat round sprinkles so they don't bleed.***A gallon sized plastic baggie will work too.