Line an 8x8-inch pan with parchment or foil, leaving an overhang for easy removal, and line a large sheet pan with parchment or a silicone liner; set both aside.
Place the whole Oreos (cookies with creme) in a food processor or blender and pulse until they become fine crumbs; reprocess any large pieces. Transfer crumbs to a large mixing bowl.
Add the softened cream cheese to the Oreo crumbs and beat with a stand mixer or hand mixer until fully combined and smooth.
Press the mixture evenly into the prepared 8x8-inch pan, compressing to create a uniform layer. Cover and refrigerate for at least 2 hours (or freeze for 1 hour) until firm.
Lift the chilled mixture from the pan using the overhang and place on a cutting board. Use a heart-shaped cookie cutter to cut out hearts; gather scraps and reroll to cut additional hearts or form small balls.
Place the chocolate and coconut oil in a microwave-safe bowl and microwave in 15-second increments, stirring between each, until melted and smooth; alternatively melt in a double boiler. Let cool about 5 minutes so it won’t melt the truffles.
Dip each heart into the melted chocolate to coat evenly, lift with a fork, tap off excess chocolate, and use a toothpick to pop any air bubbles. Slide the coated truffle onto the prepared sheet pan using a table knife.
Optionally sprinkle with Oreo crumbs immediately or wait until the chocolate sets slightly, then drizzle with melted white chocolate if desired.
Refrigerate the dipped truffles for at least 1 hour to allow the chocolate to fully set before serving.