Line a small baking sheet with parchment paper. Spread semisweet chocolate onto parchment paper in an even layer. Scatter all over with pretzels and red, pink and white sprinkles.
Transfer white chocolate to a piping bag (or a ziplock bag snipped at one corner) and pipe white chocolate into the center of each pretzel until the middle is filled entirely. Place a heart sprinkle in the center of each pretzel. Refrigerate until set, about 1 hour.
Recipe by 5* trending recipes with videos at https://food.theffeed.com/2019/02/10/valentines-day-bark/