Warm a sharp paring knife under hot running water, then dry it, and use it to trim each sandwich cookie into a rough heart shape, re-warming the knife between cuts as it cools.

Line a baking sheet with parchment paper.

Melt the chocolate in a heatproof bowl set over a pan of barely simmering water, stirring until smooth, about 4 minutes.

Dip the bottom half of each cookie heart into the melted chocolate, leaving the top half with the cream filling visible.

Let the excess chocolate drip off for a few seconds, then lay the cookie flat on the lined baking sheet, filling side up.

Scatter sprinkles over the wet chocolate on each cookie immediately after dipping.

Let the cookies set at room temperature for 15 minutes, until the chocolate is firm and no longer shiny.