01 - Peel and slice the bananas. Combine them in a blender with the Greek yogurt, honey or maple syrup, and vanilla extract. Blend until completely smooth and creamy, scraping down the sides as needed.
02 - Place the dark chocolate and coconut oil in a microwave-safe bowl. Heat in 20-second intervals, stirring between each, until fully melted and smooth. Alternatively, melt over a double boiler, stirring constantly.
03 - Pour half of the banana mixture into the popsicle molds, filling each one about halfway. Drizzle a layer of the melted chocolate into each mold over the banana base.
04 - Gently drag a skewer or small knife through the chocolate drizzle in each mold to create a marbled effect. Avoid over-mixing to keep distinct swirls visible.
05 - Divide the remaining banana mixture among the molds, filling them to the top. Repeat the chocolate drizzle and swirl for a second layer of marbling throughout each popsicle.
06 - Insert a popsicle stick into the center of each mold, pressing gently until stable. If desired, sprinkle chopped roasted nuts or mini chocolate chips over the exposed surface.
07 - Transfer the filled molds to the freezer and freeze for a minimum of 4 hours, or until the popsicles are completely firm throughout.
08 - Briefly run the outside of each mold under warm water for 10 to 15 seconds to loosen. Gently pull the popsicle from the mold by the stick and serve immediately.