01 - Place the peeled and sliced bananas into a blender. Add the Greek yogurt, honey or maple syrup, and vanilla extract. Blend on medium-high until the mixture is completely smooth and creamy, about 30 to 45 seconds.
02 - Combine the dark chocolate and coconut oil in a microwave-safe bowl. Microwave in 20-second intervals, stirring between each, until fully melted and smooth. Alternatively, melt over a double boiler, stirring gently until homogeneous.
03 - Pour half of the banana mixture into the popsicle molds, filling each one about halfway. Drizzle a generous layer of the melted chocolate over the banana base in each mold. Use a skewer or small knife to gently swirl the chocolate into the banana layer, creating a marbled effect.
04 - Divide the remaining banana mixture evenly among the molds, filling them to the top. Drizzle more melted chocolate over the surface and swirl again with a skewer for additional marbling throughout.
05 - Insert a popsicle stick into the center of each mold, pressing gently until stable. If desired, sprinkle the tops with chopped roasted nuts or mini chocolate chips before the mixture begins to set.
06 - Transfer the filled molds to the freezer and let them set for a minimum of 4 hours, or until the popsicles are completely firm and frozen through.
07 - To release each popsicle, briefly run the outside of the mold under warm water for 10 to 15 seconds. Gently pull the stick to slide the popsicle free. Serve immediately.